Answer:
6.25 μg/mL
Explanation:
When a dilution is made, the mass of the solute is conserved (Lavoiser's law), so the mass pipetted will be the mass in the assay. The mass is the concentration (C) multiplied by the volume (V). If the pipet solution is called 1, and the assay 2:
m1 = m2
C1*V1 = C2*V2
C1 = 250 μg/mL
V1 = 25 μL
V2 = 975 μL + 25 μL = 1000 μL (is the final volume of the assay after the addition of LDH)
250*25 = C2*1000
C2 = 6.25 μg/mL
The final concentration of LDH in the assay is 6.25 ug/ml.
Explanation:To determine the final concentration of LDH in the assay, you need to consider the volumes of LDH and assay buffer used. In this case, you pipet 25 ul of 250 ug/ml LDH into 975 ul of assay buffer. To calculate the final concentration, you can use the formula:
Final Concentration = (Volume of LDH x Concentration of LDH) / Total Volume of Assay
Substituting the values, the final concentration of LDH in the assay is:
Final Concentration = (25 ul x 250 ug/ml) / (25 ul + 975 ul) = 6.25 ug/ml
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What kind of intermolecular forces act between a hydrogen chloride molecule and a hydrogen iodide molecule?
Answer:
Since ΔEN > 0, the bond is covalent polar and the molecule is polar (dipole). Since ΔEN > 0, the bond is covalent polar and the molecule is polar (dipole). HI and ClF interact through a dipole-dipole force
Explanation:
Final answer:
Dipole-dipole forces act between a hydrogen chloride molecule and a hydrogen iodide molecule due to the partially positive hydrogen atom and partially negative chlorine atom in a hydrogen chloride molecule.
Explanation:
Dipole-dipole forces, which are attractive forces between polar molecules, act between a hydrogen chloride molecule and a hydrogen iodide molecule. These forces occur because a hydrogen chloride molecule has a partially positive hydrogen atom and a partially negative chlorine atom. In a collection of many hydrogen chloride molecules, the oppositely charged regions of neighboring molecules will align themselves near each other.
Fluoridation is the process of adding fluorine compounds to drinking water to help fight tooth decay. A concentration of 1 ppm of fluorine is sufficient for the purpose (1 ppm means one part per million, or 1 g of fluorine per 1 million g of water). The compound normally chosen for fluoridation is sodium fluoride, which is also added to some toothpastes. Calculate the quantity of sodium fluoride in kilograms needed per year for a city of 50,000 people if the daily consumption of water per person is 115.0 gallons. (Sodium fluoride is 45.0 percent fluorine by mass. 1 gallon = 3.79 L; 1 ton=2000lb; 1 lb= 453.6 g; density of water =1.0 g/mL)
Answer:
The quantity of sodium fluoride is 17,676,14 kilograms is needed per year for a city of 50,000 people.
Explanation:
Population of the city = 50,000
Volume of water consumed by an individual in day= 115.0 gallons
Volume of water consumed by 50,000 people in day: V
V = 115.0 gallons × 50,000 = 5,750,000 gallons
1 gallon = 3.79 L
[tex]V=5,750,000 gallons=5,750,000\times 3.79 L = 21,792,500 L[/tex]
[tex]V=21,792,500 L=21,792,500,000 mL[/tex]
( 1L = 1000 mL)
Mass of water = m
Density of water = d = 1.0 g/mL
[tex]m=d\times V=1.0 g/mL\times 21,792,500,000 mL=21,792,500,000 g[/tex]
Concentration of Fluorine in water = 1 ppm = 1 gram of F /1 million grams of water
Then mass of fluorine present in 21,792,500,000 g of water:
[tex]\frac{1}{10^6}\times 21,792,500,000 g=21,792.5 g[/tex]
Mass of sodium fluoride with 21,792.5 g of F = M
Percentage of fluorine in NaF = 45.0 %
[tex]45\%=\frac{21,792.5 g}{M}\times 100[/tex]
M = 48,427.78 g = 48.427 kg ( 1g = 0.001 kg)
48.427 kg of NaF should be added to water in day for city population.
Amount of NaF needed per year for city with 50,000 population :
(1 year = 365 days)
[tex]48.427 kg\times 365=17,676.14 kg[/tex]
The quantity of sodium fluoride is 17,676,14 kilograms is needed per year for a city of 50,000 people.
Requiring a fluorine concentration of 1 ppm in a city's water supply for 50,000 people, each consuming 115 gallons of water per day, would necessitate 17,677 kg of sodium fluoride per annum.
Explanation:First, we'd need to calculate the total amount of water consumed by the entire city in a year. This would be 50,000 people x 115 gallons/person/day x 365 days/year = 2,098,750,000 gallons/year. After converting this to liters (1 gallon = 3.79 L), the total water consumption is 7,954,625,000 L/year or 7,954,625,000,000 g/year (since 1L of water = 1g).
For a fluorine concentration of 1 ppm (1 g of fluorine/1,000,000 g of water), the yearly requirement of fluorine is 7,954,625 g of fluorine. Sodium fluoride is 45.0 percent fluorine by mass, so to get this amount of fluorine, we will need 7,954,625 g / 0.45 = 17,676,944 g or 17,677 kg of sodium fluoride per year.
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What is a pseudo–noble gas configuration? Give an example of one ion from Group 3A(13) that has it.
Explanation:
Pseudo-noble gas configuration which can also be called pseudo inert configuration is when elements have fully filled d-orbital, along with s- and p- orbitals. Examples are ions of elements, this is because they lose their valence electrons to be fully filled in order to have a stable octet.
Example of Group 3A(13) ion is Aluminium ion; Al3+. Al3+ takes up the configuration of Neon when it loses its 3 valence electrons.
Electronic configuration of Al and Al3+
Al = [Ne] 3s2 3p1
Al3+ = 1s2 2s2 2p6
A pseudo-noble gas configuration occurs when an ion or atom has an electron configuration that resembles that of a noble gas. An example of an ion from Group 3A(13) that has a pseudo-noble gas configuration is aluminium (Al3+).
Explanation:A pseudo-noble gas configuration refers to the electron configuration of an ion or atom that resembles that of a noble gas. This occurs when an ion gains or loses electrons to acquire the same electron configuration as a noble gas. An example of an ion from Group 3A(13) that has a pseudo-noble gas configuration is aluminium (Al3+).
Aluminum has an electron configuration of 1s2 2s2 2p6 3s2 3p1 in its ground state. When it loses its three valence electrons, its configuration becomes 1s2 2s2 2p6, which is the same as that of the noble gas, neon (Ne). Therefore, aluminium has a pseudo-noble gas configuration.
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The flame test for sodium is based on the intense yelloworange emission at 589 nm; the test for potassium is based on its emission at 404 nm. When both elements are present, the Na⁺ emission is so strong that the K⁺ emission can’t be seen, except by looking through a cobalt-glass filter. (a) What are the colors of these Na⁺ and K⁺ emissions? (b) What does the cobalt-glass filter do? (c) Why are the oxidizing agents in fireworks made of KClO₄ or KClO₃, rather than the corresponding sodium salts?
Answer:
a) The flame test of Na, at 589nm will show a golden yellow color when the sodium ion is emitted. These is due to the electropositive nature of the alkali metals.
While the flame test for K at 404nm will ignite a violet color when the Potassium ion is emitted. This properties are due to the high electropositive nature of the group1 elements which also indicate their strong reducing agent.
b) The cobalt glass filter act as hindrance during the flame test to seperate or filter the golden yellow color caused as a result of the presence of the sodium, as it makes the violet color to be more visible.
c) These is due to the Oxidizing ability of KClO₄ or KClO₃ compared to the salts of sodium. Also is the low solubility of the two salts and their solubility constant (Ksp) compared to sodium salts.
Explanation:
a) The flame test of Na, at 589nm will show a golden yellow color when the sodium ion is emitted. These is due to the electropositivity nature of the alkali metals.
While the flame test for K at 404nm will ignite a violet color when the Potassium ion is emitted. This properties are due to the high electropositivity nature of the group1 elements which also indicate their strong reducing agent.
b) The cobalt glass filter act as hindrance during the flame test to seperate or filter the golden yellow color caused as a result of the presence of the sodium, as it makes the violet color to be more visible.
c) These is due to the Oxidizing ability of KClO₄ or KClO₃ compared to the salts of sodium. Also is the low solubility of the two salts and their solubility constant (Ksp) compared to sodium salts.
A small portion of a crystal lattice is sketched below. What is the name of the unit cell of this lattice? Your answer must be a word, a very short phrase, or a standard abbreviation. Spelling counts!
The unit cell described is called the simple cubic unit cell, which contains one atom total due to each corner atom being shared by eight unit cells.
Explanation:The name of the unit cell of the crystal lattice you've described is the simple cubic unit cell, also known as primitive cubic unit cell. In a simple cubic lattice, the unit cell that repeats itself in all directions to form the entire lattice is a cube with atoms at its corners. These atoms effectively 'touch' each other, and each corner atom is shared among eight unit cells; hence, each unit cell contains one-eighth of an atom at each of its eight corners, totaling one atom per unit cell.
g What is the molarity of an aqueous solution that is 2.50 % glucose (C6H12O6) by mass? Assume that the density of the solution is 1.04 g/cm3
Answer:
0.144 M
Explanation:
First, we will calculate the mass/volume percent (% m/v) using the following expression.
% m/v = % m/m × density
% m/v = 2.50 % × 1.04 g/cm³
% m/v = 2.60 %
This means that there are 2.60 grams of solute per 100 cm³ (100 mL) of solution. The molarity of glucose is:
M = mass of glucose / molar mass of glucose × liters of solution
M = 2.60 g / 180.16 g/mol × 0.100 L
M = 0.144 M
A solution is made by dissolving 58.125 g of sample of an unknown, nonelectrolyte compound in water. The mass of the solution is exactly 750.0 g. The boiling point of this solution is 100.220 ∘ C . What is the molecular weight of the unknown compound?
Answer:
195.52 g/mol
Explanation:
Answer:
195.52 g/mol
Explanation:
1.) ΔT = Kb * molality
2.) (100.22-100) = 0.512 * molality
3.) 0.22 = 0.512 * molality
4.) 0.22/0.512 =( 0.512 * molality)/ 0.512
5.) 0.4297 = molality
6.) molality = mol of solute/ kg of solvent
7.) 0.4297 = mol of solute / (0.750- 0.058125)
8.) 0.4297 = mol of solute / 0.69175
9.) (0.4297 = mol of solute / 0.69175) * 0.69175
10.) mol of solute = 0.29729
11.) mol = mass / mw therefore mw = mass/ mol
12.) mw = 58.125g / 0.29729mol
13.) mw = 195.125 g/mol
Please be mindful I did not consistently write conversions or write out units to show cancellations.
To determine the molecular weight of the unknown compound, one would need to calculate the boiling point elevation, then the molality of the solution, and finally rearrange the formula to solve for the molar mass based on the given masses of solute and solvent.
Explanation:The student's question pertains to the calculation of the molecular weight of an unknown compound using the boiling point elevation method in Chemistry. To find the molecular weight of the unknown compound, the boiling point elevation (ΔTb) first needs to be determined, using the observed boiling point and the normal boiling point of water (100°C). Then, using the boiling point elevation constant (Kb for water), and the mass of the solute and solvent, the molality (m) of the solution can be calculated. The molar mass (M) of the unknown compound is then found by rearranging the formula ΔTb = i ⋅ Kb ⋅ m, where i is the van't Hoff factor (which is 1 for a nonelectrolyte compound) and solving for M.
Since we know the mass of the solute and solvent and the boiling point elevation, the molality can be calculated with m = (moles of solute) / (kilograms of solvent). The moles of solute is molar mass dependent, so when we rearrange to solve for molar mass, we get M = (mass of solute in grams) / (molality ⋅ kg of solvent).
To solve the problem, the steps are as follows:
Determine the boiling point elevation (ΔTb) by subtracting the normal boiling point of water from the given boiling point of the solution.Calculate molality (m) using the boiling point elevation constant for water (Kb) and the determined ΔTb.Find the molar mass (M) by rearranging the formula to solve for M based on the mass of solute and the calculated molality.A metallic object holds a charge of −4.8 × 10−6 C. What total number of electrons does this represent? (e = 1.6 × 10−19 C is the magnitude of the electronic charge.)
Answer:
[tex]n=3.0\times 10^{13}[/tex]
Explanation:
Charge on 1 electron = [tex]-1.6\times 10^{-19}\ C[/tex]
The expression for charge is:-
[tex]Charge=n\times q_e[/tex]
Given that:- Charge = [tex]-4.8\times 10^{-6}\ C[/tex]
[tex]-4.8\times 10^{-6}=n\times (-1.6\times 10^{-19})[/tex]
[tex]n=\frac{4.8\times 10^{-6}}{1.6\times 10^{-19}}=3.0\times 10^{13}[/tex]
Total number of electrons, n = [tex]3.0\times 10^{13}[/tex]
The total number of electrons the charge represent is 3.0 × 10¹³
Calculating number of electronsFrom the question, we are to calculate the total number of electrons
Using the formula,
Q = ne
Where Q is the total charge
n is the number of electrons
and e is the charge of an electron
From the given information,
q = - 4.8 × 10⁻⁶ C
(NOTE: The negative sign indicates the type of charge)
e = 1.6 × 10⁻¹⁹ C
Then,
4.8 × 10⁻⁶ = n × 1.6 × 10⁻¹⁹
n = [tex]\frac{4.8 \times 10^{-6} }{1.6 \times 10^{-19} }[/tex]
n = 3.0 × 10¹³
Hence, the total number of electrons the charge represent is 3.0 × 10¹³
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How is it possible for a protein to change over 70% of its amino acids and still fold in the same way?
The complete question is
Comparison of a homeodomain protein from yeast and Drosophila shows that only 17 of its 60 amino acids are identical. How is it possible for a protein to change over 70% of its amino acids and still fold in the same way?
Answer:
Many different strings of the amino acid can give rise to the identical protein folds. The amino acid differences between the Drosophila and homeodomain proteins from yeast are the functional proteins which do not change their structure and function.
There is a several amount of folding required which can cause change in the protein structure.
There is a basic functional proteins common in both the organism which do not change its structure and function.
A gas of unknown pressure is contained in a vertical cylinder with a piston, of mass 1.1 kg and diameter 10.0 cm. The piston is free to move with negligible friction. A weight of mass 2.0 kg is placed on top of the piston. Knowing the atmospheric pressure (1.0 atm), find the pressure of the gas, in pascals.
Answer:
The answer the question, what is the pressure of the gas, in pascals is 101195.73 Pa
Explanation:
Firstly we list out the known variables
The known variables are
mass of piston = 1.1 kg, diameter of piston, D = 10.0 cm = 0.1 m
mass of weight = 2.0 kg atmospheric pressure = 1.0 atm
In this question the quantity required is the presssure of the gas in the cylinder after placing a weght on the piston
To solve this, we note that Pressure = Force per unit area
= Force/area, hence
We compute the area of the piston thus
Area = (πD²)÷4 = 0.0079 m²
While the sum of the mass of the piston and the added weight = 1.1 kg + 2.0 kg = 3.1 kg
The weight of the added mass and piston that is their force on the gas = W = Mass × gravity = 3.1 kg × 9.81 m/s² = 30.411 N
Therefore the pressure = 30.411N/(0.0079 m²) = 3870.73 Pascals
The pressure of the gas = pressure due to the piston and the added weight + pressure due to the atmosphere
thus pressure of the gas = 3870.73 Pa + 1.0 atm =3870.73 Pa + 101325 Pa =101195.73 Pa
The pressure of the gas, in pascals is 101195.73 Pa
In a first order decomposition in which the rate constant is 0.0808 sec-1, how long will it take (in minutes) until 0.358 mol/L of the compound is left, if there was 0.52 mol/L at the start? (give answer to 3 decimal places)?
Answer:
t = 4.62 sec
Explanation:
For every first order reaction the rate constant K is given as
[tex]k =(\frac{2.303}{t} )log\frac{[A_{o} ]}{[A]}[/tex]
[tex][A_{o} ] = initial concentration = 0.52\frac{mol}{L}[/tex]
[tex][A] =final concentration = 0.358 \frac{mol}{L}[/tex]
[tex]K = 0.0808 sec^{-1}[/tex]
[tex]t = (\frac{2.303}{K} ) log (\frac{[A_{o} ]}{[A]} )[/tex]
[tex]= (\frac{2.303}{0.0808} )log (\frac{0.52}{0.358} )[/tex]
t = 4.62 sec
Answer:0.0771mins
Explanation:The first order rate law eqn =Ca=Caoe^-kt
Ca=final mass remaining
Cap=initial mass
K=rate or decay constant
t=time
e=exponential
ca=0.358
cao=0.52
K=0.0808/sec
Substituting,we have
0.358=0.52e^-0.0808t
0.358/0.52=e^-0.0808t
0.688=e^-0.0808t
Taking naturaing logarithm of both sides(ln of both sides)
ln(0.688)=-0.0808t
-0.3739=-0.0808t
t=0.3739/0.0808
t=4.628secs
In mins,4.628/60=0.0771mins.
A vertical piston-cylinder device contains water and is being heated. During the heating process, 70 kJ of heat is transferred to the water, and heat losses from the side walls amount to 8 kJ. The piston rises as a result of evaporation, changing the volume by 0.5 m3. When the atmospheric pressure is 1 atm and the mass of the piston is 50 kg and its cross-sectional area is 0.05 m2, determine the change in the energy of the water for this process.
The change in the energy of the water for this process is calculated as 11.3375 kJ, considering the heat transferred and work done.
To determine the change in energy of the water within the piston-cylinder setup, we need to account for the heat transferred and the work done. The given values are:
Heat transferred to water: 70 kJHeat losses from the side walls: 8 kJVolume change: 0.5 m³Atmospheric pressure: 1 atm (101.325 kPa)Mass of the piston: 50 kgCross-sectional area of the piston: 0.05 m²The net heat energy (Q) added to the system is:
[tex]Q_{net[/tex] = 70 kJ - 8 kJ = 62 kJFor the work done by the system, we use:
W = P × ΔVwhere W is work, P is pressure (101.325 kPa), and ΔV is the volume change (0.5 m³). Converting kPa to kJ by recognizing 1 kPa×m³ = 1 kJ, we get:
W = 101.325 kPa × 0.5 m³ = 50.6625 kJUsing the first law of thermodynamics, the change in internal energy (ΔU) is:
ΔU = Qnet - WSubstituting the values, we get:
ΔU = 62 kJ - 50.6625 kJ = 11.3375 kJTherefore, the change in the energy of the water for this process is 11.3375 kJ.
For your research project, your group is planning to treat embryos with acetaminophen at a concentration of 50 ug/L plus varying concentrations of dextromethorphan between O and 100 uM. You have stock solutions of 500 ug/L acetaminophen and 1 mM dextromethorphan to work with. If you wanted to treat some embryos with final concentrations of 50 ug/L acetaminophen and 20 uM dextromethorphan in a total volume of 10 ml, how would you make up 9 ml of solution containing both acetaminophen and dextromethorphan, to which you could add 1 ml of embryo water containing the embryos? A. Add 0.5ml of 500 ug/1 acetaminophen and 0.5 ml of 1 mM dextromethorphan to 8 ml of water B. Add 1 ml of 500 ug/l acetaminophen and 0.2 ml of 1 mM dextromethorphan to 8.8 ml of water. C. Add 0.1 ml of 500 ug/l acetaminophen and 0.5 ml of 1 mM dextromethorphan to 8.4 ml of water. D. Add 1 ml of 500 ug/I acetaminophen and 0.2 ml of 1 mM dextromethorphan to 7.8 ml of water. E. Add 1 ml of 500 ug/I acetaminophen and 2 ml of 1 mM dextromethorphan to 6 ml of water.
Answer:
D
Explanation:
When a dilution is made, a volume of the stock solution is collected and then is mixed to the solvent. The total amount of the solute (number of moles or mass), must be equal in the volume of the sample and at the final volume, because of the Lavoiser's law (the matter can't be created nor destructed).
The mass or the number of moles is the concentration (C) multiplied by the volume (V), so, if 1 is the sample of the stock solution, and 2 the diluted solution:
C1*V1 = C2*V2
The final volume of the solution is 10 mL. So, let's identify the volume needed for each stock solution.
Acetaminophen
C1 = 500 ug/L
C2 = 50 ug/L
500*V1 = 50*10
V1 = 1 mL
Dextromethorphan
C1 = 1 mM = 1000 uM
C2 = 20 uM
1000*V1 = 20*10
V1 = 0.2 mL
So, the volume of water needed is the total less the volume of the stocks solutions less the volume of the embryo water:
V = 10 - 1 - 1 - 0.2 = 7.8 mL
Thus, to to the solution, it's necessary to add at 1 mL of the embryo water 1 ml of 500 ug/I acetaminophen and 0.2 ml of 1 mM dextromethorphan, and 7.8 ml of water.
In a concentrated solution there is ____.a. no solvent c. a small amount of soluteb. a large amount of solute d. no solute
Answer:a large amount of solute
Explanation:
A solution is composed of a solute and a solvent. If the amount of solute is greater than that of solvent, the solution is concentrated. A concentrated solution contains quite a large amount of solute while a dilute solution contains less amount of solute. This is the difference between diluted and concentrated solutions.
Answer:
Answer:a large amount of solute
Explanation:
A solution is composed of a solute and a solvent. If the amount of solute is greater than that of solvent, the solution is concentrated. A concentrated solution contains quite a large amount of solute while a dilute solution contains less amount of solute. This is the difference between diluted and concentrated solutions.
Explanation:
A solution of NaCl ( aq ) is added slowly to a solution of lead nitrate, Pb ( NO 3 ) 2 ( aq ) , until no further precipitation occurs. The precipitate is collected by filtration, dried, and weighed. A total of 12.11 g CaCl2 ( s ) is obtained from 200.0 mL of the original solution.
Answer:
0.218 M of Pb(NO3)2
Explanation:
Equation of the reaction
Pb(NO3)2(aq) + 2NaCl(aq) --> PbCl2(s) + 2NaNO3(aq)
1 mole of Pb(NO3)2 reacts to precipitate 1 mole of PbCl2
Molar mass of PbCl2 = 207 + (35.5*2)
= 278 g/mol
Number of moles of PbCl2 precipitated = mass/molar mass
= 12.11/278
= 0.04356 mol
Since 0.04356 moles of PbCl2 was precipitated, therefore by stoichiometry; 0.04356 moles of Pb(NO3)2 reacted.
Molarity is defined as the number of moles of solute in 1 liter of solution.
Molarity = number of moles/volumes
= 0.04356/0.2
= 0.218 M
Ammonium carbamate (NH2COONH4) is a salt of carbamic acid that is found in the blood and urine of mammals. At 250.°C, Kc = 1.58 × 10−8 for the following equilibrium:
NH2COONH4(s) ⇌ 2 NH3(g) + CO2(g)
If 11.51 g of NH2COONH4 is put into a 0.500−L evacuated container, what is the total pressure at equilibrium? atm
Answer:
The total pressure at equilibrium is 0.07503 atm
Explanation:
The partial pressure of the product at equilibrium will be calculated as follows;
Kp = Kc[RT]³
given;
equilibrium constant Kc = 1.58 X 10⁻⁸
gas constant R = 0.0821 L.atm/mol.K
temperature T = (250 +273) = 523 k
Kp = 1.58 X 10⁻⁸ *(0.0821)³ *(523)³ = 1.251 X 10⁻³
NH₂COONH₄(s) ⇌ 2NH₃(g) + CO₂
NH₂COONH₄(s): Kp = 0, since it is in solid state
2NH₃(g) + CO₂: Kp = 1.251 X 10⁻³
I.C.E Analysis on the product
2NH₃(g) CO₂
I : 0 0
C : 2x x
E : (2x-0) (x-0)
At equilibrium, E: (2x-0)(x-0) = 1.251 X 10⁻³
(2x)(x) = 1.251 X 10⁻³
2x² = 1.251 X 10⁻³
x² = (1.251 X 10⁻³)/2
x² = 6.255 X 10⁻⁴
x = √(6.255 X 10⁻⁴)
x = 0.02501 atm
Partial pressure of 2NH₃(g) = 2x = 2(0.02501 atm) = 0.05002 atm
Partial pressure of CO₂ = x = 0.02501 atm
Total pressure = P(NH₃(g)) +P(CO₂)
Total pressure = 0.05002 atm + 0.02501 atm = 0.07503 atm
Therefore, the total pressure at equilibrium is 0.07503 atm
From data provided, the total pressure at equilibrium is 0.203 atm.
What is the total pressure at equilibrium?The total pressure, Ptotal at equilibrium is calculated from the equation of the reaction given below:
NH2COONH4(s) ⇌ 2 NH3(g) + CO2(g)From the equation of the reaction, If x moles of ammonium carbamate decomposes, it will produce 2x moles of NH3(g) and x moles of CO2(g).
Ammonium carbamate is a solid, and so it does not appear in the expression for Kc.
Kc = 1.58 × 10^-8
Therefore:
Kc = [NH3(g)]^2[CO2(g)]
Kc = (2x)^2(x) = 4x^3
1.58 × 10-8 = 4x^3
Thus, x = 0.00158 M
Hence:
[NH3(g)] = 2 × 0.00158 = 0.00316 M
[CO2(g)] = 0.00158 M
From the ideal gas equation:
PV = nRTP = nRT/Vwhere
R = 0.08206 L.atm/K.molT = 250°C = 523 KAlso, concentration is given by:
c = n/VTherefore, P = cRT.
Substituting and calculating for Ptotal:
Ptotal = (0.00316 M) × RT + (0.00158 M) × RT
= ((0.00316 + 0.00158) M) × (0.08206) × ((523) K)
Ptotal = 0.203 atm
Therefore, the total pressure at equilibrium is 0.203 atm.
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A 50/50 blend of engine coolant and water (by volume) is usually used in an automobile's engine cooling system. If a car's cooling system holds 5.60 gal, what is the boiling point of the solution? For the calculation, assume that at normal filling conditions, the densities of engine coolant and water are 1.11 g/mL and 0.998 g/mL respectively. Also, assume that the engine coolant is pure ethylene glycol ( HOCH 2 CH 2 OH ) , which is non‑ionizing and non‑volatile, and that the pressure remains constant at 1.00 atm. The boiling‑point elevation constant for water will also be needed.
Answer:
109.09°C
Explanation:
Given that:
the capacity of the cooling car system = 5.6 gal
volume of solute = volume of the water; since a 50/50 blend of engine coolant and water (by volume) is used.
∴ [tex]\frac{5.60}{2}gallons = 2.80 gallons[/tex]
Afterwards, the mass of the solute and the mass of the water can be determined as shown below:
mass of solute = [tex](M__1}) = Density*Volume[/tex]
[tex]= 1.1g/mL *2.80*\frac{3785.41mL}{1gallon}[/tex]
[tex]= 11659.06grams[/tex]
On the other hand; the mass of water = [tex](M__2})= Density*Volume[/tex]
[tex]= 0.998g/mL *2.80*\frac{3785.41mL}{1gallon}[/tex]
[tex]= 10577.95 grams[/tex]
Molarity = [tex]\frac{massof solute*1000}{molarmassof solute*massofwater}[/tex]
= [tex]\frac{11659.06*1000}{62.07*10577.95}[/tex]
= 17.757 m
≅ 17.76 m
∴ the boiling point of the solution is calculated using the boiling‑point elevation constant for water and the Molarity.
[tex]\Delta T_{boiling} = k_{boiling}M[/tex]
where,
[tex]k_{boiling}[/tex] = 0.512 °C/m
[tex]\Delta T_{boiling}[/tex] = 100°C + 17.56 × 0.512
= 109.09 °C
A molecular solid coexists with its liquid phase at its melting point. The solid-liquid mixture is heated, but the temperature does not change while the solid is melting.
The best explanation for this phenomenon is that the heat absorbed by the mixture:
A. is lost to the surroundings very quickly
B. is used in overcoming the intermolecular attractions in the solid
C. is used in breaking the bonds within the molecules of the solid
D. causes the nonbonding electrons in the molecules to move to lower energy levels
The best explanation for this phenomenon is that the heat absorbed by the mixture is lost to the surroundings very quickly. Hence option B is correct.
What is mixture?Mixture is defined as a substance consisting of two or more unrelated chemicals that are not chemically linked. The two categories of mixtures are heterogeneous and homogeneous mixtures. While heterogeneous mixtures include distinct components, homogenous mixtures appear consistent throughout.
Although the mixture of solid and liquid is heated, the temperature remains constant as the solid melts. The best explanation for this phenomena is that the heat that the mixture absorbs is swiftly transferred to the environment and used to overcome the intermolecular forces.
Thus, the best explanation for this phenomenon is that the heat absorbed by the mixture is lost to the surroundings very quickly. Hence option B is correct.
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Final answer:
The heat absorbed by the solid-liquid mixture at its melting point is used in overcoming the intermolecular attractions in the solid, allowing it to transition into the liquid phase without an increase in temperature.
Explanation:
When a solid coexists with its liquid phase at its melting point, the heat absorbed by the mixture is used in overcoming the intermolecular attractions in the solid. As a solid is heated, the particles vibrate more rapidly and gain enough energy to overcome the attractive forces within the solid. This allows the solid to transition into the liquid phase without an increase in temperature. The heat added during melting is not lost to the surroundings quickly or used in breaking the bonds within the molecules of the solid, but rather in overcoming the intermolecular attractions in the solid.
Consider the reaction with the rate law, Rate = k{BrO3-}{Br-}{H+}2 By what factor does the rate change if the concentration of H+ is decreased by a factor of 4? Just put in the number as a whole number or fraction?
The rate changes by a factor of 1/16 when the concentration of H+ is decreased by a factor of 4 in the given rate law.
Explanation:The reaction with the rate law Rate = k{BrO3-}{Br-}{H+}2 indicates that the rate of the reaction is directly proportional to the concentration of H+ raised to the second power. Thus, if the concentration of H+ is decreased by a factor of 4, the rate of the reaction would decrease by a factor of 42 or 16. Therefore, the rate changes by a factor of 1/16 when the concentration of H+ decreases by a factor of 4.
The rate law for the given reaction is Rate = k{BrO3-}{Br-}{H+}^2. If the concentration of H+ is decreased by a factor of 4, it means the new concentration of H+ would be 1/4 of the original concentration. Since the rate law is quadratic with respect to H+, the rate would change by a factor of (1/4)^2, which is 1/16. Therefore, the rate would decrease by a factor of 1/16 or 0.0625.
The rate of the reaction changes by a factor of [tex]\(\frac{1}{16}\)[/tex] (or decreases to [tex]\(\frac{1}{16}\)[/tex] of its original rate) when the concentration of[tex]\( \text{H}^+ \)[/tex] is decreased by a factor of 4.
Given the reaction with the rate law:
[tex]\[ \text{Rate} = k[\text{BrO}_3^-][\text{Br}^-][\text{H}^+]^2 \][/tex]
We need to determine how the rate changes if the concentration of[tex]\( \text{H}^+ \)[/tex] is decreased by a factor of 4.
Step-by-Step Explanation:
1. Initial Rate Law Expression:
[tex]\[ \text{Rate}_1 = k[\text{BrO}_3^-][\text{Br}^-][\text{H}^+]^2 \][/tex]
2. Change in [tex]\( \text{H}^+ \)[/tex] Concentration:
Let's denote the initial concentration of[tex]\( \text{H}^+ \)[/tex]as [tex]\([ \text{H}^+ ]_1\)[/tex]. If the concentration of[tex]\( \text{H}^+ \)[/tex] is decreased by a factor of 4, the new concentration will be:
[tex]\[ [ \text{H}^+ ]_2 = \frac{[ \text{H}^+ ]_1}{4} \][/tex]
3. New Rate Law Expression:
Substitute the new concentration of [tex]\( \text{H}^+ \)[/tex] into the rate law:
[tex]\[ \text{Rate}_2 = k[\text{BrO}_3^-][\text{Br}^-]\left( \frac{[ \text{H}^+ ]_1}{4} \right)^2 \][/tex]
4. Simplify the Expression:
[tex]\[ \text{Rate}_2 = k[\text{BrO}_3^-][\text{Br}^-]\left( \frac{[ \text{H}^+ ]_1^2}{4^2} \right) \][/tex]
[tex]\[ \text{Rate}_2 = k[\text{BrO}_3^-][\text{Br}^-]\left( \frac{[ \text{H}^+ ]_1^2}{16} \right) \][/tex]
5. Relate [tex]\( \text{Rate}_2 \) to \( \text{Rate}_1 \)[/tex] :
From the initial rate law, we know that:
[tex]\[ \text{Rate}_1 = k[\text{BrO}_3^-][\text{Br}^-][\text{H}^+]_1^2 \][/tex]
So, we can write:
[tex]\[ \text{Rate}_2 = \frac{\text{Rate}_1}{16} \][/tex]
6. Factor by Which the Rate Changes:
The rate decreases by a factor of 16.
Consider two acids: CH3CO2H (acetic acid, pKa = 4.8) and C6H5CO2H (benzoic acid, pKa = 4.2). Which acid is the stronger acid? Select the single best answer.
a. benzoic acid
b. acetic acid
Answer:
Benzoic acid
Explanation:
The strength of an acid is principally a measure of its dissociative capabilities in aqueous solutions. While strong acids dissociate completely in solution, weak acids dissociates only partially.
The relative strength of an acid can be obtained from its pKa value. The pKa value is the negative logarithm of the concentration of the Ka value.
Stronger acids have a pKa value usually negative. This is a pointer to the fact that the lower the pKa value, the stronger the strength of the acid in question.
Relatively therefore, Benzoic acid is stronger than acetic acid because it has a lesser value for pKa
The strength of an acid is determined by its pKa value, with lower values indicating stronger acids. Therefore, between CH3CO2H (acetic acid, pKa = 4.8) and C6H5CO2H (benzoic acid, pKa = 4.2), benzoic acid is the stronger acid.
Explanation:When comparing acids, the strength of an acid is determined by its pKa value. The lower the pKa value, the stronger the acid is. In this case, the two acids that are being compared are CH3CO2H (acetic acid, pKa = 4.8) and C6H5CO2H (benzoic acid, pKa = 4.2). Therefore, given that the pKa of benzoic acid is lower than that of acetic acid, we can conclude that benzoic acid is the stronger acid. To summarize, the best answer to the question 'Which acid is the stronger acid, CH3CO2H (acetic acid) or C6H5CO2H (benzoic acid)?' is option a. benzoic acid.
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Predict which member of each pair will be more acidic. Explain your answers. (a) methanol or tert-butyl alcohol (b) 2-chloropropan-1-ol
Answer:
A. Methanol
B. 2-chloropropan-1-ol
C. 2,2-dichloroethanol
D. 2,2-difluoropropan-1-ol
Explanation:
Primary alcohols are stronger acids than secondary alcohols which are stronger than tertiary alcohols.
This trend is so because of the stability of the alkoxide ion formed(stabilising the base, increases the acidity). A more stabilised alkoxide ion is a weaker conjugate base (dissociation of an acid in water).
By electronic factors, When there are alkyl groups donating electrons, the density of electrons on th O- will increase a d thereby make it less stable.
By stearic factors, More alkyl group bonded to the -OH would mean the bulkier the alkoxide ion which would be harder to stabilise.
Down the group of the periodic table, basicity (metallic character) decreases as we go from F– to Cl– to Br– to I– because that negative charge is being spread out over a larger volume that is electronegativity decreases down the group.
Electronegative atoms give rise to inductive effect and a decrease in indutive effects leads to a decrease in acidity. Therefore an Increasing distance from the -OH group lsads to a decrease in acidity.
From above,
A. Methanol
B. 2-chloropropan-1-ol
C. 2,2-dichloroethanol
D. 2,2-difluoropropan-1-ol
Methanol is more acidic than tert-butyl alcohol because it forms a more stable alkoxide ion on deprotonation. Likewise, 2-chloropropan-1-ol is more acidic than propan-1-ol due to the stabilizing effect of its chlorine atom on the alkoxide ion.
Explanation:The acidity of an alcohol is determined by the stability of the resulting alkoxide ion on deprotonation. In other words, an alcohol that can form a more stable alkoxide ion will be more acidic.
(a) Between methanol and tert-butyl alcohol, methanol would be more acidic. This is because the alkoxide ion formed when methanol loses a proton is more stable. In tert-butyl alcohol, the large, bulky tert-butyl group hinders the solvation of the alkoxide ion, making it less stable and the alcohol less acidic.
(b) 2-chloropropan-1-ol would be more acidic than propan-1-ol because the electron-withdrawing chlorine atom stabilizes the alkoxide ion, making the alcohol more acidic.
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Which element would you expect to be less metallic?
(a) Sb or As (b) Si or P (c) Be or Na
Explanation:
When we move across a period from left to right then there will occur an increase in electronegativity and also there will occur an increase in non-metallic character of the elements.
As both arsenic (As) and antimony (Sb) are group 15 elements. And, on moving down the group increases metallic character hence, Sb will be more metallic than As. Therefore, As is less metallic in nature than Sb.
Silicon (Si) is a group 14 element and phosphorus (P) is a group 15 element. And, both of them lie in period 3 and since, non-metallic character increases on moving from left to right along a period. Therefore, phosphorus (P) is less metallic than silicon (Si).
Sodium (Na) is a group 1A element (also known as alkali metal) and beryllium (Be) is a group 2A element (also known as alkaline earth metal). Hence, Be is less metallic than Na because on moving from left to right there occurs an increase in non-metallic character.
Magnesium Oxide decomposes to produce 3.54 grams of oxygen gas. How many grams of magnesium oxide decomposed?
Explanation:
Magnesium oxide
It is MgO Its molecular mass is : 24 +16=40 g When MgO decomposes it forms = 3.54 g of oxygen gas when 40 g of MgO decomposes it forms = 16g of oxygen or we can say that : 16g of oxygen is produced when 40 g of MgO is decomposed . 1g of oxygen will be formed from =40/16g of MgO 3.54 g of oxygen will be formed = 40/16 x 3.54 =8.85g of MgOFor each of the following sublevels, give the n and l values and the number of orbitals: (a) 6g; (b) 4s; (c) 3d.
Answer:
(a) 6g. Shell 6, n = 6. Subshell g, l = 4. Number of orbitals in sublevel = 9
(b) 4s. Shell 4, n = 4. Subshell s, l = 0. Number of orbitals in sublevel = 1
(c) 3d. Shell 3, n = 3. Subshell d, l = 2. Number of orbitals in sublevel = 5
Explanation:
The rules for electron quantum numbers are:
1. Shell number, 1 ≤ n, n = 1, 2, 3...
2. Subshell number, 0 ≤ l ≤ n − 1, orbital s - 0, p - 1, d - 2, f - 3
3. Orbital energy shift, -l ≤ ml ≤ l
4. Spin, either -1/2 or +1/2
So,
(a) 6g. Shell 6, n = 6. Subshell g, l = 4. Number of orbitals in sublevel = 2l+1 = 9
(b) 4s. Shell 4, n = 4. Subshell s, l = 0. Number of orbitals in sublevel = 2l+1 = 1
(c) 3d. Shell 3, n = 3. Subshell d, l = 2. Number of orbitals in sublevel = 2l+1 = 5
(a) 6g Shell 6, n = 6. Subshell g, l = 4. Number of orbitals in sublevel = 9
(b) 4s Shell 4, n = 4. Subshell s, l = 0. Number of orbitals in sublevel = 1
(c) 3d Shell 3, n = 3. Subshell d, l = 2. Number of orbitals in sublevel = 5
What are Quantum numbers?There are a total of four quantum numbers: the principal quantum number (n), the orbital angular momentum quantum number (l), the magnetic quantum number (ml), and the electron spin quantum number (ms).
The rules for electron quantum numbers are:
1. Shell number, 1 ≤ n, n = 1, 2, 3...
2. Subshell number, 0 ≤ l ≤ n − 1, orbital s - 0, p - 1, d - 2, f - 3
3. Orbital energy shift, -l ≤ ml ≤ l
4. Spin, either -1/2 or +1/2
(a) 6g. Shell 6, n = 6. Subshell g, l = 4. Number of orbitals in sublevel = 2l+1 = 9
(b) 4s. Shell 4, n = 4. Subshell s, l = 0. Number of orbitals in sublevel = 2l+1 = 1
(c) 3d. Shell 3, n = 3. Subshell d, l = 2. Number of orbitals in sublevel = 2l+1 = 5
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How many grams of Aldol product can be produced from the complete reaction of 0.2 grams of vanillin with an excess of acetone in the presence of aqueous base? Enter only the number with two significant figures.
Answer:
There is 0.25 grams of C11H12O3 produced
Explanation:
Step1: Data given
vanillin = C8H8O3
Mass of vanillin = 0.2 grams
Molar mass of vanillin = 152.15 g/mol
Acetone = 58.08 g/mol
Step 2: The balanced equation
C8H8O3 + C3H6O → H2O + C11H12O3
Step 3: Calculate moles of C8H8O3
Moles C8H8O3 = mass / molar mass
Moles C8H8O3 = 0.2 grams / 152.15 g/mol
Moles C8H8O3 = 0.0013 moles
Step 4: Calculate moles of C11H12O3
For 1 mol vanillin we need 1 mol acetone to produce 1 mol C11H12O3
Step 5: Calculate mass of C11H12O3
Mass C11H12O3 = moles * molar mass
Mass C11H12O3 = 0.0013 moles * 192.21 g/mol
Mass C11H12O3 = 0.25 grams
There is 0.25 grams of C11H12O3 produced
A 3.3×10-2 mg sample of a protein is dissolved in water to make 0.25 mL of solution. The osmotic pressure of the solution is 0.56 torr at 25°C. What is the molar mass of the protein?
Answer: 4376.6g/mol
Explanation:Please see attachment for explanation
The molar mass of the protein is 4376.6 g/mol.
What is molar mass?The molar mass of a chemical compound is defined as the mass of a sample divided by the amount of substance in that sample, measured in moles.
Solution:
Given, the mass of protein is 3.3×10-2 mg
Mass converted into gram = 3.3×10-2 mg = M 0.000033 g
Therefore, xg of the protein dissolve in 1 L
xg pf protein =[tex]\bold{\dfrac{0.000033}{0.00025} = 0.132\; g/L}[/tex]
Given, the osmotic pressure of 0.56 torr.
[tex]\bold{\pi = 0.56\;torr =\dfrac{0.56}{760} = 0.00737\; atm p}[/tex]
Thus, the volume of the solution is 0.007 L
Given, Temperature = 25 °C
Converting into kelvin = 25+273 = 298 k.
R = 0.082 atm.
Now, by the formula [tex]\bold{M_2= \dfrac{W_2RT}{\pi V}}[/tex]
[tex]\bold{M_2= \dfrac{0.132\times0.082\times298}{0.00737\times0.007} =4376.6 \;g/mol}[/tex]
Thus, the molar mass of protein is 4376.6 g/mol.
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Calculate the distance olive oil (a lipid) could move in a membrane in 15 seconds assuming the diffusion coefficient is 1 μm2/s. Use the equation where S is distance traveled, t is time, and D is the diffusion coefficient.S = (4Dt)^1/2
Answer:
The answer according to the given equation is S = 0.00077 cm
Explanation:
According to this equation
S = (4Dt)^1/2
S = (4* 1^e-8 * 15)^0.5
S = 0.00077 cm
According to the Approximation equation for diffusion time
t ≅ S^2 / 2D
S = 0.00055 cm
Using the equation S = (4Dt)^1/2, the average distance olive oil can move in a membrane in 15 seconds is calculated to be 7.75 micrometers.
Explanation:To calculate the distance that olive oil, a lipid, could move in a membrane in 15 seconds with a diffusion coefficient of 1 μm2/s, we use the equation S = (4Dt)1/2. Plugging in the values, we get S = (4 × 1 μm2/s × 15 s)1/2. We perform the calculation as follows:
Calculate the product of 4, the diffusion coefficient (D), and time (t): 4 × 1 μm2/s × 15 s = 60 μm2Take the square root of 60 μm2 to find the distance: √60 μm2 = 7.75 μmThe average distance that olive oil can move in the membrane in 15 seconds is 7.75 micrometers.
Suppose a 0.049 M aqueous solution of sulfuric acid ( H 2 SO 4 ) is prepared. Calculate the equilibrium molarity of SO 4 − 2. You'll find information on the properties of sulfuric acid in the ALEKS Data resource. Round your answer to 2 significant digits.
The equilibrium molarity of SO4 2- in a 0.049 M aqueous solution of H2SO4 will be approximately 0.049 M after the initial dissociation, as sulfuric acid is a strong acid and dissociates completely in its first step, and the second dissociation is generally weaker.
Explanation:The question involves the dissociation of sulfuric acid (H2SO4) in water, which occurs in two steps. The first dissociation is strong, with the equation H2SO4 (aq) → 2H+ (aq) + SO42- (aq). Because sulfuric acid is a strong acid, the initial dissociation is essentially complete, and the equilibrium molarity of SO42- will be equal to the initial molarity of H2SO4, barring any further reactions.
Given a 0.049 M solution of H2SO4, after the first dissociation, we have 0.049 M of SO42-. The second dissociation of HSO4- to form SO42- is weak. However, without the acid dissociation constant (Ka) value or any other provided equilibrium concentrations, one cannot calculate the additional contribution of SO42- from the second dissociation. Therefore the most straightforward answer, assuming the second dissociation's contribution is negligible compared to the first, is that the equilibrium molarity of SO42- due to the first dissociation is approximately 0.049 M.
Give the characteristic of a first order reaction having only one reactant.a. The rate of the reaction is not proportional to the concentration of the reactantb. The rate of the reaction is proportional to the square of the concentration of the reactantc. The rate of the reaction is proportional to the square root of the concentration of the reactantd. The rate of the reaction is proportional to the natural logarithm of the concentration of the reactante. The rate of the reaction is directly proportional to the concentration of the reactant
Answer:
E) The rate of the reaction is directly proportional to the concentration of the reactant.
Explanation:
Give the characteristic of a first order reaction having only one reactant.
A) The rate of the reaction is not proportional to the concentration of the reactant.
B) The rate of the reaction is proportional to the square of the concentration of the reactant.
C) The rate of the reaction is proportional to the square root of the concentration of the reactant.
D) The rate of the reaction is proportional to the natural logarithm of the concentration of the reactant.
E) The rate of the reaction is directly proportional to the concentration of the reactant.
Answer:
The rate of the reaction is directly proportional to the concentration of the reactant.
Explanation:
2. Mrs. Roberts, in a diabetic coma, has just been admitted to Noble Hospital. Her blood pH indicates that she is in severe acidosis, and measures are quickly instituted to bring her blood pH back within normal limits. (a) Define pH and note the normal pH of blood. (b) Why is severe acidosis a problem?
Answer:
Explanation:
a) The pH can be define as the measurement of the hydrogen or hydroxide ion concentration in a solution. The pH for blood is 7.4. In severe acidosis condition the pH of blood is 7.35 or lower.
b) Severe acidosis is a condition which is caused due to the overproduction of acid and building up of acid in the blood. This occurs due to the excessive loss of bicarbonate from the blood or buildup of carbon dioxide in the blood. This leads to poor functioning of the lungs and depressed breathing.
The severe acidosis is critical condition because because it can adversely affect the cell membranes, muscle contraction, and function of the kidneys and neural activity of the body.
Final answer:
pH is a scale used to measure how acidic or alkaline a substance is, with normal blood pH being between 7.35 and 7.45. Severe acidosis, often due to diabetic ketoacidosis, disrupts normal bodily functions, impairs oxygen transport, and can lead to life-threatening symptoms like dehydration, lethargy, and coma if untreated.
Explanation:
pH is a measure of the acidity or alkalinity of a solution, where a pH below 7 is acidic, and a pH above 7 is alkaline. The normal pH of blood is tightly regulated between 7.35 and 7.45. Severe acidosis is a condition where the blood pH falls significantly below this range.
Severe acidosis is problematic because it can disrupt biological processes. Specifically, it affects the ability of hemoglobin to transport oxygen and may lead to symptoms like labored breathing, dehydration, lethargy, and loss of appetite. The condition can be life-threatening, as it may lead to a coma if not promptly treated.
Diabetic ketoacidosis is a common cause of acidosis in diabetic individuals, occurring when excessive ketone bodies in the blood lower the pH well below normal levels, often leading to a value around 6.9, thus disrupting the acid-base balance and necessitating medical intervention.