Answer:
a. The balanced chemical equation for the reaction
[tex]NH_3(g)+HCl(g)\rightarrow NH_4Cl(g)[/tex]
b. HCl is the limiting reagent.
c. 7.3295 grams of ammonium chloride could form from the reaction mixture in part (b).
d. 0.6715 grams of ammonia is left over in the reaction mixture in part b.
Explanation:
a. The balanced chemical equation for the reaction
[tex]NH_3(g)+HCl(g)\rightarrow NH_4Cl(g)[/tex]
b.
Moles of ammonia =[tex]\frac{3.0 g}{17 g/mol}=0.1765 mol[/tex]
Moles of HCl = [tex]\frac{5.0 g}{36.5 g/mol}=0.1370 mol[/tex]
According to reaction, 1 mole of HCl reacts with 1 mole of ammonia . Then 0.1370 moles of HCl will react with :
[tex]\frac{1}{1}\times 0.1370 mol=0.1370 mol[/tex] of ammonia
Hence, HCl is the limiting reagent.
c.
Since, HCl is a limiting reagent amount of ammonium chloride will depend upon moles of HCl.
According to reaction, 1 mole of HCl gives with 1 mole of ammonium chloride . Then 0.1370 moles of HCl will give :
[tex]\frac{1}{1}\times 0.1370 mol=0.1370 mol[/tex] of ammonium chloride
Mass of 0.1370 moles of ammonium chloride :
53.5 g/mol × 0.1370 mol = 7.3295 g
7.3295 grams of ammonium chloride could form from the reaction mixture in part (b).
d.
Moles of ammonia =[tex]\frac{3.0 g}{17 g/mol}=0.1765 mol[/tex]
HCl is a limiting reagent and ammonia is an excessive reagent.
According to reaction, 1 mole of HCl reacts with 1 mole of ammonia . Then 0.1370 moles of HCl will react with :
[tex]\frac{1}{1}\times 0.1370 mol=0.1370 mol[/tex] of ammonia
Moles of Ammonia reacted = 0.1370 mol
Moles of ammonia left unreacted = 0.1765 mol - 0.1370 mol = 0.0395 mol
Mass of 0.0395 moles of ammonia :
0.0395 mol × 17 g/mol = 0.6715 g
0.6715 grams of ammonia is left over in the reaction mixture in part b.
A solution contains 3.1 mM Zn(NO3)2 and 4.2 mM Ca(NO3)2. The p-function for Zn2+ is _____, and the p-function for NO3- is _____.
Answer: The p-function of [tex]Zn^{2+}[/tex] and [tex]NO_3^{-}[/tex] ions are 2.51 and 2.14 respectively.
Explanation:
p-function is defined as the negative logarithm of any concentration.
We are given:
Millimolar concentration of zinc nitrate = 3.1 mM
Millimolar concentration of calcium nitrate = 4.2 mM
Converting this into molar concentration, we use the conversion factor:
1 M = 1000 mM
Concentration of zinc nitrate = 0.0031 M = 0.0031 mol/L1 mole of zinc nitrate produces 1 mole of zinc ions and 2 moles of nitrate ions
Concentration of zinc ions = 0.0031 M
Concentration of nitrate ions in zinc nitrate, [tex]M_1=(2\times 0.0031)=0.0062M[/tex]
Concentration of calcium nitrate = 0.0042 M = 0.0042 mol/L1 mole of calcium nitrate produces 1 mole of calcium ions and 2 moles of nitrate ions
Concentration of calcium ions = 0.0042 M
Concentration of nitrate ions in calcium nitrate, [tex]M_2=(2\times 0.0042)=0.0084M[/tex]
To calculate the concentration of nitrate ions in the solution, we use the equation:
[tex]M=\frac{M_1V_1+M_2V_2}{V_1+V_2}[/tex]
Putting values in above equation, we get:
[tex]M=\frac{(0.0062\times 1)+(0.0084\times 1)}{1+1}\\\\M=0.0073M[/tex]
Calculating the p-function of zinc ions and nitrate ions in the solution:
For zinc ions:[tex]\text{p-function of }Zn^{2+}\text{ ions}=-\log[Zn^{2+}][/tex]
[tex]\text{p-function of }Zn^{2+}\text{ ions}=-\log(0.0031)\\\\\text{p-function of }Zn^{2+}\text{ ions}=2.51[/tex]
For nitrate ions:[tex]\text{p-function of }NO_3^{-}\text{ ions}=-\log[NO_3^{-}][/tex]
[tex]\text{p-function of }NO_3^{-}\text{ ions}=-\log(0.0073)\\\\\text{p-function of }NO_3^{-}\text{ ions}=2.14[/tex]
Hence, the p-function of [tex]Zn^{2+}[/tex] and [tex]NO_3^{-}[/tex] ions are 2.51 and 2.14 respectively.
The p-function values for Zn2+ and NO3- are 9.6 and 15.5, respectively.
The p-function for Zn2+ is 9.6, and the p-function for NO3- is 15.5.
In 2009, a team from Northwestern University and Western Washington University reported the preparation of a new "spongy" material composed of nickel, molybdenum, and sulfur that excels at removing mercury from water. The density of this new material is 0.20 g/cm^3, and its surface area is 1242 m^2 per gram of material.
A) Calculate the volume of a 40.0-mg sample of this material. (Express your answer to two significant figures and include the appropriate units.)
B) Calculate the surface area for a 40.0-mg sample of this material.
Express your answer to three significant figures and include the appropriate units.
C) A 10.0-mL sample of contaminated water had 7.748 mg of mercury in it. After treatment with 10.0 mg of the new spongy material, 0.001 mg of mercury remained in the contaminated water. What percentage of the mercury was removed from the water?
Express your answer to four significant figures.
D) What is the final mass of the spongy material after the exposure to mercury?
Express your answer to three significant figures and include the appropriate units
Answer:
A) 0.20 cm³
B) 49.7 m²
C) 99.99%
D) 17.7 mg
Explanation:
A) The density of a material represents the mass that it occupies in a "piece" of volume. Thus, the density (d) is the mass (m) divided by the volume (v):
d =m/v
If the mass is 40.0 mg = 0.04 g, and the density is 0.20 g/cm³, the volume is:
0.20 = 0.04/v
v = 0.04/0.20
v = 0.20 cm³
B) The surface area (S) is the are that is presented in each gram of the material, so, it's the area (a) divided by the mass (m):
S = a/m
If the mass is 40.0 mg = 0.04 g, and the surface area is 1242 m²/g, so:
1242 = a/0.04
a = 49.7 m²
C) The percent of mercury removed is the mass removed divided by the initial mass, this multiplied by 100%. The mass removed is the initial mass (m0) less the final mass (m), so:
%removed = [(7.748 - 0.001)/7.748] *00%
%removed = 99.99%
D) The final mass of the spongy material is it mass (10 mg) plus the mass removed of the mercury (7.748 - 0.001 = 7.747 mg), so:
m = 10 + 7.747
m = 17.747 mg
m = 17.7 mg
Final answer:
This detailed answer explains how to calculate the volume, surface area, percentage of mercury removed, and final mass of a new material used to remove mercury from water.
Explanation:
A) To calculate the volume of a 40.0-mg sample of the material, you can use the formula: Volume = Mass / Density. Therefore, Volume = 40.0 mg / 0.20 g/cm³ = 200 cm³.
B) The surface area for a 40.0-mg sample can be calculated by multiplying the specific surface area by the mass: 1242 m²/g × 40.0 mg = 49680 m².
C) The percentage of mercury removed from the water is: ((Initial mercury mass - Final mercury mass) / Initial mercury mass) × 100 = ((7.748 mg - 0.001 mg) / 7.748 mg) × 100 = 99.9874%.
D) The final mass of the spongy material after exposure to mercury is the initial mass minus the mass used: 40.0 mg - 10.0 mg = 30.0 mg.
Calculate the work engergy gained or lost by the system when a gas expands from 35 to 55 l against a constant external presure of 3atm.
Answer: The work energy lost by the system is -6078 Joules
Explanation:
According to first law of thermodynamics:
[tex]\Delta E=q+w[/tex]
[tex]\Delta E[/tex]=Change in internal energy
q = heat absorbed or released
w = work done or by the system
w = work done by the system=[tex]-P\Delta V[/tex] {Work is done by the system as the final volume is greater than initial volume and is negative}
where P = pressure = 3 atm
[tex]\Delta V[/tex] = change in volume = (55-35) L = 20 L
w =[tex]-3atm\times (20)L=-60Latm=-6078Joules[/tex]
{1Latm=101.3J}
Thus work energy lost by the system is -6078 Joules
Indicate the number of unpaired electrons in He. Express your answer as an integer.
Answer : The number of unpaired electrons in helium is, 0
Explanation :
As we are given that the element is helium. The symbol of helium element is, (He).
The atomic number of helium element is, 2 that means it has 2 number of electrons.
Electronic configuration : It is defined as the representation of electrons around the nucleus of an atom.
Number of electrons in an atom are determined by the electronic configuration.
The electronic configuration of helium element is: [tex]1s^2[/tex]
There is no unpaired electrons in helium element.
Hence, the number of unpaired electrons in helium is, 0
The number of unpaired electrons in He is 0.
Helium (He) is an element with an atomic number of 2, which means it has 2 protons in its nucleus and, in its neutral state, 2 electrons in its electron configuration. The electron configuration of helium follows the principles of quantum mechanics, where electrons fill the lowest energy levels first according to the Pauli exclusion principle and Hund's rule.
The first energy level (n=1) can hold up to 2 electrons, and for helium, this energy level is filled with 2 electrons. These electrons occupy the 1s orbital, which is the only orbital available at this energy level. According to the Pauli exclusion principle, no two electrons can have the same set of quantum numbers, so one electron fills the 1s orbital with a spin of +1/2 (up), and the other fills it with a spin of -1/2 (down). This results in both electrons being paired with opposite spins, canceling each other out.
Since all electrons in helium are paired, there are no unpaired electrons. Therefore, the number of unpaired electrons in a helium atom is 0. This makes helium a noble gas, which is characterized by having a full valence shell and being chemically inert due to the lack of unpaired electrons available for chemical bonding.
Calcium hypochlorite (Ca(OCl)2, MW = 142.983 g/mol) is often used as the source of the hypochlorite ion (OCl–, MW = 51.452 g/mol) in solutions used for water treatment. A student must prepare 50.0 mL of a 55.0 ppm OCl– solution from solid Ca(OCl)2, which has a purity of 94.0%.
A) Calculate the mass of the impure reagent required to prepare the solution. Assume the density of the solution is 1.00 g/mL.
B) Which of the following methods would work best to accurately prepare 50.0 mL of the 55.0 ppm OCl– solution?
Use an analytical balance to weigh out an amount of reagent larger than what was determined in part A. In a volumetric flask, combine the reagent and water to create a solution with a concentration greater than 55.0 ppm. Use a pipet to transfer a portion of the concentrated solution to a separate 50.0 mL volumetric flask and dilute to the line with water to create a solution with a concentration of 55.0 ppm.
Use an analytical balance to weigh out an amount of reagent larger than what was determined in part A. In a volumetric flask, combine the reagent and water to create a solution with a concentration greater than 55.0 ppm. Use a graduated cylinder to transfer a portion of the more concentrated solution to a 50.0 mL volumetric flask and dilute to the line with water to create a solution with a concentration of 55.0 ppm.
Use an analytical balance to weigh out the amount of reagent determined in part A. Transfer the reagent to a 50.0 mL volumetric flask, add water to the line, and mix thoroughly.
Use an analytical balance to weigh out the amount of reagent determined in part A. Then use a graduated cylinder to measure out 50.0 mL of water. Combine the reagent and water in a 50.0 mL volumetric flask and mix it thoroughly.
Answer:
the mass of the impure reagent required to prepare the solution is approximately 0.41875 g.
Explanation:
A) To calculate the mass of the impure reagent required to prepare the solution, we can use the formula:
mass = volume x concentration x molar mass
First, let's calculate the moles of OCl- required:
moles = volume x concentration
Given that the volume is 50.0 mL and the concentration is 55.0 ppm (parts per million), we convert the concentration to a decimal by dividing it by 1,000,000:
55.0 ppm = 55.0 / 1,000,000 = 0.000055
moles = 50.0 mL x 0.000055 = 0.00275 mol
Now, let's calculate the mass of Ca(OCl)2 needed:
mass = moles x molar mass
Given that the molar mass of Ca(OCl)2 is 142.983 g/mol, we have:
mass = 0.00275 mol x 142.983 g/mol = 0.39395 g
However, the Ca(OCl)2 is impure, with a purity of 94.0%. To find the mass of the impure reagent, we divide the mass by the purity percentage and multiply by 100:
mass of impure reagent = (0.39395 g / 94.0%) x 100 = 0.41875 g
Therefore, the mass of the impure reagent required to prepare the solution is approximately 0.41875 g.
B) The best method to accurately prepare 50.0 mL of the 55.0 ppm OCl- solution is:
- Use an analytical balance to weigh out the amount of reagent determined in part A. Transfer the reagent to a 50.0 mL volumetric flask, add water to the line, and mix thoroughly.
This method ensures that the desired concentration is achieved by precisely measuring the required mass of the impure reagent and diluting it to the desired volume in a volumetric flask. The use of an analytical balance and a volumetric flask helps to ensure accuracy and precision in the preparation of the solution.
The other methods mentioned (using a pipet or graduated cylinder) may not provide the same level of accuracy and precision as using a volumetric flask, which is specifically designed for precise volume measurements.
If the mass percentage composition of a compound is 72.1% Mn and 27.9% O, its empirical formula is
Answer:
MnO- Manganese Oxide
Explanation:
Empirical formula: This is the formula that shows the ratio of elements
present in a
compound.
How to determine Empirical formula
1. First arrange the symbols of the elements present in the compound
alphabetically to determine the real empirical formula. Although, there
are exceptions to this rule, E.g H2So4
2. Divide the percentage composition by the mass number.
3. Then divide through by the smallest number.
4. The resulting answer is the ratio attached to the elements present in
a compound.
Mn O
% composition 72.1 27.9
Divide by mass number 54.94 16
1.31 1.74
Divide by the smallest number 1.31 1.31
1 1.3
The resulting ratio is 1:1
Hence the Empirical formula is MnO, Manganese oxide
It takes 261 kJ/mol to eject electrons from a certain metal surface. What is the longest wavelength of light (nm) that can be used to eject electrons from the surface of this metal via the photoelectric effect?
Answer: 459 nm
Explanation:
The relation between energy and wavelength of light is given by Planck's equation, which is:
[tex]E=\frac{Nhc}{\lambda}[/tex]
where,
E = energy of the light = [tex]261 kJ=261000J[/tex] (1kJ=1000J)
N= avogadro's number = [tex]6.023\times 10^{23}[/tex]
h = Planck's constant = [tex]6.626\times 10^{-34}Js[/tex]
c = speed of light = [tex]3\times 10^8m/s[/tex]
[tex]\lambda[/tex] = wavelength of light = ?
Putting the values in the equation:
[tex]261000J=\frac{6.023\times 10^{23}\times 6.626\times 10^{-34}Js\times 3\times 10^8m/s}{\lambda}[/tex]
[tex]\lambda=4.587\times 10^{-7}m=459nm[/tex] [tex]1nm=10^{-9}m[/tex]
Thus the longest wavelength of light that can be used to eject electrons from the surface of this metal via the photoelectric effect is 459 nm
Rank the following compounds in order of decreasing acid strength using periodic trends. Rank the acids from strongest to weakest. To rank items as equivalent, overlap them.
H2Se
HBr
H2O
HI
Explanation:
It is known that acidic strength of hydrides of same group tends to increase when we move from top to bottom in a group. On the other hand, acidic strength of hydrides of same period elements increases when we move from left to right in a period.
As both bromine and iodine belongs to the same group. Also, selenium and oxygen are same group elements. Therefore, their acidic strength increases on moving down the group.
Therefore, we can conclude that acidic strength of given compounds from strongest to weakest is as follows.
HI > HBr > [tex]H_{2}Se[/tex] > [tex]H_{2}O[/tex]
To rank the acids in decreasing acid strength using periodic trends, consider the size, electronegativity, and presence of lone pairs of electrons. HI is the strongest acid, followed by HBr, H2O, and H2Se.
Explanation:To rank the acids in order of decreasing acid strength using periodic trends, we need to consider the size and electronegativity of the atoms. The larger the atom, the weaker the acid, and the more electronegative the atom, the stronger the acid. Additionally, we can consider the presence of lone pairs of electrons, as they increase the acidity.
HI - Iodine (I) is larger and less electronegative than the other halogens. It also has a lone pair of electrons, making it the strongest acid.HBr - Bromine (Br) is larger and less electronegative than chlorine (Cl), and it also has a lone pair of electrons. It is the second strongest acid.H2O - Oxygen (O) is smaller and more electronegative than the halogens. It does not have a lone pair of electrons, making it a weaker acid than the halogens.H2Se - Selenium (Se) is larger and less electronegative than sulfur (S). However, it does not have a lone pair of electrons, making it the weakest acid.Learn more about Periodic trends here:https://brainly.com/question/32813617
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In a reaction involving reactants in the gas state, how does increasing the partial pressures of the gases affect the reaction rate?
Answer:
The reaction rate is increased.
Explanation:
The pressure is the force the gas molecules do when hitting each other and the walls of the container they're. The partial pressure is the pressure of a substance in a mixture would have if it was alone at the same conditions.
Thus, when the partial pressure increases, it means that the molecules collide more often. The reaction happens when the molecules collide in the right way, so, if the collisions are happening more often, the rate must be higher.
When the equation below is correctly balanced, what are the coefficients of Pb and H20, respectively? Pb + H2O + O2 => Pb(OH)2 A. 1,2 B. 2,1 C. 2,2 D. 1,1 E. none of these
Answer:
C
Explanation:
Pb + H2O + O2 => Pb(OH)2
Number of oxygen atom on left = 3
Number of oxygen atom on the right = 2
To balance number of oxygen
Change the coefficient of Pb and H2O to two each
2Pb + 2H2O + O2 => 2Pb(OH)2
The coefficient of Pb and H2O is 2,2
The correct coefficients for Pb and H₂O when balancing the equation Pb + H₂O + O₂ ⇒ Pb(OH)₂ are 1 and 2, respectively; therefore, the answer is A. 1,2. This ensures that the chemical equation is fully balanced with the correct number of atoms for each element on both sides.
Explanation:When balancing the chemical equation Pb + H₂O + O₂ ⇒ Pb(OH)₂, the correct coefficients for Pb and H₂O, respectively, are 1 and 2. Balancing chemical equations requires that the same number of atoms for each element be present on both sides of the equation. Starting with lead (Pb), we see that one Pb atom is needed on both sides, so we keep the coefficient for Pb as 1.
Next, we balance the hydrogen atoms. There are two hydrogens in each hydroxide ion, and since there are two hydroxide ions in Pb(OH)₂, this means there are a total of four hydrogen atoms in the product. To balance this, we need 2 molecules of H₂O (since each molecule of water contains two hydrogen atoms, giving us the four we need), making the coefficient for H₂O equal to 2.
Lastly, the oxygen atoms will balance themselves once H and Pb are balanced. With 2 H₂O molecules, we have 2 oxygen atoms, and the Pb(OH)₂ molecule has 2 oxygen atoms as well, which means we don't need any additional O₂ for balance. The balanced equation is 1 Pb + 2 H₂O + O₂ ⇒ 1 Pb(OH)₂. Therefore, the correct answer is A. 1,2.
What is the name of the molecular compound SF 5? sulfur pentafluoride sulfur hexafluoride sulfur heptafluoride monosulfur tetrafluoride none of the above
Answer: sulfur pentafluoride
Explanation:
The rules for naming of binary molecular compound :
In the given formula, the lower group number element is written first in the name and keep its element name and the higher group number is written second.
First element i.e. sulphur in the formula is named first and keep its element name.
1) Gets a prefix if there is a subscript on it such as mono for 1, di for 2, tri for 3 and so on.
Second element i.e. fluorine is named second.
1) Use the root of the element name, if it is an anion then use suffix (-ide).
2) Always use a prefix on the second element such as mono for 1, di for 2, tri for 3 and so on.
Therefore, the chemical name of compound [tex]SF_5[/tex] is sulfur pentafluoride
The name of the molecular compound SF₅ is sulfur pentafluoride. Therefore, option A is correct.
A molecular compound is a compound composed of two or more nonmetallic elements. In molecular compounds, atoms are joined together by covalent bonds, which involve the sharing of electrons between atoms.
Examples of molecular compounds include water (H₂O), carbon dioxide (CO₂), methane (CH₄), and ammonia (NH₃). Molecular compounds often have specific naming conventions based on the elements present and their respective ratios, such as using prefixes to indicate the number of atoms for each element.
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Gluconeogenesis must use "bypass reactions" to circumvent three reactions in glycolysis that are highly exergonic and essentially irreversible. Which of the following correctly matches the glycolytic reaction with the gluconeogenic enzyme used in the corresponding bypass reaction?
(A) Fructose 6-phosphate -> fructose 1,6-bisphosphate; phosphofructokinase-2
(B) 2-phosphoglycerate -> phosphoenolpyruvate; phosphoglycerate kinase
(C) Phosphoenolpyruvate -> pyruvate; pyruvate kinase
(D) Glucose -> glucose 6-phosphate; glucose 6-phosphatase
(E) Glyceraldehyde 3-phosphate -> 1,3-bisphosphoglycerate; phosphoenolcarboxykinase
Answer: A & C
Explanation:
Hexokinase is also one of the enzymes.
(A) Fructose 6-phosphate -> fructose 1,6-bisphosphate; phosphofructokinase-2
(C) Phosphoenolpyruvate -> pyruvate; pyruvate kinase
In gluconeogenesis, bypass reactions circumvent irreversible steps in glycolysis. The correct matching of the glycolytic reaction and the gluconeogenic enzyme is glucose to glucose 6-phosphate via glucose 6-phosphatase.
Explanation:The process known as gluconeogenesis uses what are known as bypass reactions to circumvent three different steps in the glycolytic reaction process that are essentially irreversible. These bypass reactions occur via the use of different enzymes.
Options Analysis(A) Fructose 6-phosphate -> fructose 1,6-bisphosphate is incorrect; the conversion of fructose 6-phosphate to fructose 1,6-bisphosphate is catalyzed by phosphofructokinase-1, not phosphofructokinase-2.(B) 2-phosphoglycerate -> phosphoenolpyruvate is incorrect. This reaction is catalyzed by enolase, not phosphoglycerate kinase.(C) Phosphoenolpyruvate -> pyruvate is incorrect. In gluconeogenesis, the reaction of converting pyruvate back to phosphoenolpyruvate is aided by the enzyme pyruvate carboxylase, not pyruvate kinase.(D) Glucose -> glucose 6-phosphate; glucose 6-phosphatase is correct. In gluconeogenesis, the conversion of glucose 6-phosphate back to glucose is catalyzed by the enzyme glucose 6-phosphatase, which is absent in glycolysis.(E) Glyceraldehyde 3-phosphate -> 1,3-bisphosphoglycerate is incorrect. The conversion of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate is catalyzed by glyceraldehyde 3-phosphate dehydrogenase, not phosphoenolcarboxykinase.Learn more about Gluconeogenesis here:https://brainly.com/question/34723403
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A gas mixture is made by combining 5.4 g each of Ar , Ne , and an unknown diatomic gas. At STP, the mixture occupies a volume of 69.03 L. What is the molar mass of the unknown gas
Answer:
The unknown gas is H2
Explanation:
Step 1: Data given
A mixture contains:
5.4 grams of Ar
5.4 grams of Ne
5.4 grams of X2
Molar mass of Ar = 39.95 g/mol
Molar mass of Ne = 20.18 g/mol
Step 2: Calculate moles of gases
.Moles of Ne = 4.5grams /20.18 g/mol = 0.223 moles
Moles of Ar= 4.5 grams /39.95 g/mol = 0.113 moles
Step 3: Calculate volume of gases
Volume of Ne =22.4 * 0.223 = 5
Volume of Ar =22.4 * 0.1525 = 2.53 L
Volume of unknown gas = 69.03 - 5 - 2.53 = 61.5 L
Step 4: Calculate moles of unknown gas
Moles of unkown gas =61.5/22.4 = 2.75 moles
Step 5: Calculate molar mass of unknown gas
Molar mass = mass / moles
Molar mass = 5.4 grams /2.75 moles ≈ 2 g/mol
The unknown gas is H2
What is the pH of a 75.0 mL solution that is 0.047 M in weak base and 0.057 M in the conjugate weak acid ( K a = 7.2 × 10 − 8 ) ?
To calculate the pH of a solution containing a weak base and its conjugate weak acid, use the Henderson-Hasselbalch equation.
Explanation:To calculate the pH of a solution that contains a weak base and its conjugate acid, we need to apply the Henderson-Hasselbalch equation.
The Henderson-Hasselbalch equation is given by: pH = pKa + log([A-]/[HA]), where pKa is the negative logarithm of the acid dissociation constant (Ka), [A-] is the concentration of the conjugate base, and [HA] is the concentration of the weak acid.
In this case, the weak base has a concentration of 0.047 M and the conjugate weak acid has a concentration of 0.057 M. The pKa value of the acid is 7.2 x 10^-8. Plugging these values into the Henderson-Hasselbalch equation, we can calculate the pH of the solution.
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The pH of a 75.0 mL solution that is 0.047 M in weak base and 0.057 M in the conjugate weak acid ( K a = 7.2 × 10⁻⁸) will be approximately 7.06.
To determine the pH of a solution that contains both a weak base and its conjugate acid, we can use the Henderson-Hasselbalch equation. The equation is:
pH = pKa + log([A⁻]/[HA])
Where:
Given that the Ka for the weak acid is 7.2 x 10⁻⁸, the pKa is:
pKa = -log(Ka) = -log(7.2 x 10⁻⁸)
The concentration of the weak base ([A⁻]) is given as 0.047 M, and the concentration of the conjugate weak acid ([HA]) is 0.057 M.
Substituting into the Henderson-Hasselbalch equation:
pH = pKa + log(0.047/0.057)
Performing the calculations:
pH = 7.14 + log(0.825)
pH 7.14 - 0.084 = 7.06
Therefore, the pH of the solution is approximately 7.06.
A scientist makes a measurement and gets a value of 13.1 m. The true value is 10.0 m. Calculate the absolute and relative error of the scientist's measurement. Round your answers to a reasonable number of decimal places. Also be sure your answers include any necessary symbols.
Answer:
The absolute error = 3.1m
The relative error = 0.31
Explanation:Please see attachment for explanation
An effluent discharge with a flow of 1.5 m3/s and an ammonium-N concentration of 2 mg/L is released to a river with a flow of 12 m3/s and an ammonium-N concentration of 0.015 mg/L. What is the concentration of this mixture after they have become perfectly mixed downstream?
Answer:
the final concentration is C=0.235 mg/L
Explanation:
doing a mass balance
ammonium mass outflow = ammonium inflow from river+ effluent discharge of ammonium = 12000 L/s* 0.015 mg/L + 1500 L /s * 2 mg/L = 3180 mg/s
outflow rate = 12000 L/s+ 1500 L /s = 13500 L/s
then the final concentration is
C= ammonium mass outflow/outflow rate = 3180 mg/s/13500 L/s= 0.235 mg/L
Final answer:
To find the concentration of the mixture after becoming perfectly mixed downstream, we can use the principle of mass conservation.
Explanation:
To find the concentration of the mixture after becoming perfectly mixed downstream, we can use the principle of mass conservation. The total mass of ammonium-N in the effluent discharge is given by the product of its concentration and flow rate, while the total mass of ammonium-N in the river is given by the product of its concentration and flow rate. When the effluent discharge and river mix together, the total mass of ammonium-N remains constant.
We can use the equation:
(flow rate of effluent discharge * concentration of effluent discharge) + (flow rate of river * concentration of river) = (flow rate of mixture * concentration of mixture)
Plugging in the given values:
(1.5 m³/s * 2 mg/L) + (12 m³/s * 0.015 mg/L) = (flow rate of mixture * concentration of mixture)
Solving this equation will give us the concentration of the mixture after they have become perfectly mixed downstream.
Calculate the pH for the following weak acid.
A solution of HCOOH has 0.15M HCOOH at equilibrium. The Ka for HCOOH is 1.8×10−4. What is the pH of this solution at equilibrium?
Answer:
The answer to your question is pH = 2.28
Explanation:
Chemical reaction
HCOOH(ac) + H₂O ⇔ H₃O⁺ + HCOO⁻
I 0.15 -- 0 0
C - x -- +x +x
F 0.15 - x -- x x
Write the equation of equilibrium
[tex]ka = \frac{[H3O][HCOO]}{[HCOOH]}[/tex]
Substitution
[tex]1.8 x 10^{-4} = \frac{[x][x]}{0.15 - x}[/tex]
But 0.15 - x ≈ 0.15
[tex]1.8 x 10^{-4} = \frac{x^{2} }{0.15}[/tex]
Solve for x
x² = (0.15)(1.8 x 10⁻⁴)
Simplification
x² = 0.000027
Result
x = 0.0052
pH = -log [H₃O⁺]
Substitution
pH = - log [0.0052]
Simplification and result
pH = 2.28
The pH of a 0.15M solution of HCOOH with a Ka of 1.8×10⁻´ is calculated using an ICE table, which leads to an equilibrium pH of approximately 2.78.
To calculate the pH of a 0.15M solution of HCOOH with a Ka of 1.8×10⁻´, we can set up an ICE (Initial, Change, Equilibrium) table to find the equilibrium concentrations of the species in solution:
Initial: [HCOOH] = 0.15 M, [H⁺] = 0 M, [HCOO⁻] = 0 MChange: [HCOOH] decreases by x, [H⁺] increases by x, [HCOO⁻] increases by xEquilibrium: [HCOOH] = 0.15 - x, [H⁺] = x, [HCOO⁻] = xApplying the expression for Ka, we have:
Ka = 1.8×10⁻´ = (x)(x) / (0.15 - x)
Assuming x is small and can be ignored in the denominator, we simplify to:
Ka = x² / 0.15
Solving for x (which represents [H⁺]), we find that x is approximately equal to the square root of (Ka × [HCOOH]), thus:
[H⁺] = √(1.8×10⁻´ × 0.15) ≈ 1.65×10⁻²
To find the pH, we take the negative logarithm of [H⁺]:
pH = -log(1.65×10⁻²) ≈ 2.78
The pH of the solution at equilibrium is approximately 2.78.
When 500.0 g of water is decomposed by electrolysis and the yield of hydrogen is only 75.3%, how much hydrogen chloride can be made if the yield of hydrogen chloride in the second reaction is 69.8%? Oxygen and chlorine and in excess.
2H₂O → 2H₂ + O₂ 75.3 % yield
H₂ + Cl₂ → 2HCl 69.8% yield
The amount of hydrogen chloride that can be made is 1064 g
Why?
The two reactions are:
2H₂O → 2H₂ + O₂ 75.3 % yield
H₂ + Cl₂ → 2HCl 69.8% yield
We have to apply a big conversion factor to go from grams of water (The limiting reactant), to grams of HCl, the final product. We have to be very careful with the coefficients and percentage yields!
[tex]500.0gH_2O*\frac{1moleH_2O}{18.01 gH_2O}*\frac{2 moles H_2}{2 moles H_2O}*\frac{2.015g H_2}{1 mole H_2}*\frac{75.3 actual g}{100 theoretical g}=42.12 g H_2[/tex]
[tex]42.12H_2*\frac{1 mole H_2}{2.015gH_2}*\frac{2 moles HCl}{1 mole H_2}*\frac{36.46g}{1 mole HCl}*\frac{69.8 actualg}{100 theoreticalg} =1064gHCl[/tex]
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The amount of hydrogen chloride yield in the second reaction is 1065.7 g.
The two given reactions
2H₂O → 2H₂ + O₂ 75.3 % yield H₂ + Cl₂ → 2HCl 69.8% yieldThe amount of hydrogen gas yield in the first reaction is calculated as follows;
[tex]\frac{500 \ g\ H_2O}{18 \ g \ H_2O} \times (2 \ mol\ H_2) \times 0.753= 41.83 \ g \ H_2[/tex]
The amount of hydrogen chloride yield in the second reaction is calculated as follows;
[tex]41.83 \ g \times (36.5 \ HCl) \times 0.698 = 1065.7 \ g \ HCl[/tex]
Thus, the amount of hydrogen chloride yield in the second reaction is 1065.7 g.
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Which of the following membrane ion channels open and close in response to changes in the membrane potential?
voltage-gated channels
Answer: voltage-gated channels
Explanation:
voltage-gated Ion channels: They are proteins of multi-subunit complexes that reacts with confrontations changes that occurs in the members potential which results in the opening and closing of the pore. They mainly help to generate electrical signals within the cell membrane. The locations of the voltage-gated ion channels includes in the cell body of the neurons, on the dendrites, on the axon hillock, on the node of Ranvier, etc. Majorly, when ion channels open, it is a form of response to stimuli.
Voltage-gated channels are the membrane ion channels that open in response to changes in membrane potential, cycling through closed, open, or inactivated states depending on the cell's electrical charge.
Explanation:The membrane ion channels that open and close in response to changes in the membrane potential are known as voltage-gated channels. These channels can exist in one of three states - closed, open, or inactivated. Initially, voltage-gated ion channels are closed, but they open in response to a change in the electrical potential of the cell membrane. Specifically, when the inner membrane voltage becomes less negative in comparison to the outside, the channels sense the change through amino acids in their structure that are sensitive to charge, prompting the pore to open and allow ions to move across the membrane. Once activated, these channels will then become inactivated for a brief period, during which time they cannot open in response to a signal even if the membrane potential changes.
A 255-mL flask contains pure helium at a pressure of 746 torr . A second flask with a volume of 475 mL contains pure argon at a pressure of 726 torr . If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of helium? If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of argon?
If the two flasks are connected through a stopcock and the stopcock is opened, what is the total pressure?
Answer:
pHe = 261 torr
pAr = 472 torr
P = 733 torr
Explanation:
The final volume for both gases is the same: V₂ = 255 mL + 475 mL = 730 mL
We can find the final partial pressure of each gas using Boyle's law.
He
P₁ × V₁ = P₂ × V₂
P₂ = P₁ × V₁ / V₂
P₂ = 746 torr × 255 mL / 730 mL = 261 torr
Ar
P₁ × V₁ = P₂ × V₂
P₂ = P₁ × V₁ / V₂
P₂ = 726 torr × 475 mL / 730 mL = 472 torr
The total pressure is the sum of the partial pressures.
P = 261 torr + 472 torr = 733 torr
The element copper has two stable isotopes, copper-63 with a mass of 62.93 amu and copper-65 with a mass of 64.93 amu. From the atomic weight of Cu = 63.54 one can conclude that:
- both isotopes have the same percent natural abundance
- copper-65 has the highest percent natural abundance
- most copper atoms have an atomic mass of 63.54
- copper-63 has the highest percent natural abundance
Answer: The Cu-63 isotope has the highest percent natural abundance
Explanation:
Average atomic mass is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.
Formula used to calculate average atomic mass follows:
[tex]\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i[/tex]
We are given:
Two isotopes of Copper, which are Cu-63 and Cu-65
Average atomic mass of copper = 63.54 amu
As, the average atomic mass of copper is closer to the mass of Cu-63 isotope. This means that the relative abundance of this isotope is the highest as compared to the other isotope.
Percentage abundance of Cu-63 isotope = 69.2%
Percentage abundance of Cu-65 isotope = 30.8 %
Hence, the Cu-63 isotope has the highest percent natural abundance
An air bubble with a radius of 2.5 cm at the bottom of a lake where the temperature is 5.4 0C and the pressure is 3.2atm rises to the surface, where the temperature is 25.0 0C and the pressure is 1.0 atm. Calculate the radius of the bubble when it reaches the surface. Assume ideal gas behavior.
Answer:
3.8 cm
Explanation:
Given data
Initial pressure (P₁): 3.2 atmInitial volume (V₁): 65 cm³Volume of a sphere: V = 4/3 × π × r³ = 4/3 × π × (2.5 cm)³ = 65 cm³
Initial temperature (T₁): 5.4°C + 273.15 = 278.6 KFinal pressure (P₂): 1.0 atmFinal volume (V₂): ?Final temperature (T₂): 25.0°C + 273.15 = 298.2 KWe can find the final volume using the combined gas law.
[tex]\frac{P_{1}\times V_{1}}{T_{1}} =\frac{P_{2}\times V_{2}}{T_{2}}\\\frac{3.2atm\times 65cm^{3} }{278.6K} =\frac{1.0atm\times V_{2}}{298.2K}\\V_{2}=223cm^{3}[/tex]
The final radius of the bubble is:
V = 4/3 × π × r³
223 cm³ = 4/3 × π × r³
r = 3.8 cm
You want to make 300 mL of a 0.2000 M dilute NaOH solution from a 1.5 M stock solution. How many mL of stock solution is needed?
Answer: 40mL
Explanation: What is required for this question is to obtain the number of moles of NaOH solute in the required solution.
Number of moles of solute in solution = (Concentration of solution in mol/L) × (Volume of solution in L)
Number of moles of NaOH in the required solution = 0.2 × (300/1000) = 0.06 moles
This number of moles has to be in the volume of stock solution used to make the required solution.
Volume of stock solution needed = (Number of moles of NaOH in the stock solution that has to match that in the required solution in L)/(concentration of stock solution in mol/L)
Volume of stock solution required = 0.06/1.5 = 0.04L = 40mL
QED.
To make 300 mL of a 0.2000 M NaOH solution from a 1.5 M stock solution, you need 40 mL of the stock solution, as calculated using the dilution equation.
To find out how many milliliters of a 1.5 M stock solution is needed to make 300 mL of a 0.2000 M dilute NaOH solution, you can use the equation of dilution:
C1 times V1 = C2 times V2 where C1 and V1 are the concentration and volume of the stock solution, and C2 and V2 are the concentration and volume of the dilute solution, respectively.
The formula reorganized to solve for V1 is:
V1 = (C2 imes V2) / C1
Substituting the given values, we get:
V1 = (0.2000 M times 300 mL ) / 1.5 M
V1 = 40 mL
Therefore, you need 40 mL of the stock solution to prepare the required dilution.
The metallic radius of a lithium atom is 152 pm. What is the volume of a lithium atom in cubic meters?
Answer:
Volume of lithium atom is found to be 1.47 X 10⁻²⁹ m³
Explanation:
Let us consider the volume of atom as a sphere (but it is little complex than that). This volume is mathematically expressed as,
[tex]V=\frac{4}{3}\pi R^{3}[/tex]----------------------------------------------------------------------------------------(Eq. 1)
Here, R is the radius of lithium atom. The radius is given in picometers, so firstly let us convert it into meters
[tex]R=(152pm )(1X10^{-12}\frac{m}{pm})[/tex]
[tex]R = 1.52 X 10^{-10}m[/tex]
placing this value in Eq.1 the required result is achieved
[tex]V=\frac{4}{3}\pi {1.52X10^{-10}}^{3}[/tex]
V= 1.47 X 10⁻²⁹ m³
The volume of the lithium atom is [tex]1.47 \times 10^{-29} \ m^3[/tex].
The given parameters:
Radius of the Lithium atom, V = 152 pmThe volume of the lithium atom is calculated from the volume of a sphere as follows;
[tex]V = \frac{4}{3} \pi r^3[/tex]
where;
r is the radius of the sphere in meters[tex]\\\\V = \frac{4}{3} \times \pi \times (152 \times 10^{-12})^3\\\\V = 1.47 \times 10^{-29} \ m^3[/tex]
Thus, the volume of the lithium atom is [tex]1.47 \times 10^{-29} \ m^3[/tex]
Learn more about volume of atoms here: https://brainly.com/question/1494948
Density is an intensive physical property that relates the mass of an object to its volume. Density, which is simply the mass of an object divided by its volume, is expressed in the SI derived unit g/mLg/mL for a liquid or g/cm3g/cm3 for a solid. Most substances expand or contract when heated or cooled, so the density values for a substance are temperature dependent. A particular brand of gasoline has a density of 0.737 g/mL at 25 ?C. How many grams of this gasoline would fill a 14.6gal tank?
Answer: 40731.8 grams of this gasoline would fill a 14.6gal tank
Explanation:
Density is defined as the mass contained per unit volume.
[tex]Density=\frac{mass}{Volume}[/tex]
Given : Mass of gasoline = ?
Density of the gasoline = [tex]0.737g/ml[/tex]
Volume of the gasoline = 14.6gal = 55267.01 ml (1gal=3785.41ml)
Putting in the values we get:
[tex]0.737g/ml=\frac{mass}{55267.01ml}[/tex]
[tex]{\text {mass of gasoline}}=40731.8g[/tex]
Thus 40731.8 grams of this gasoline would fill a 14.6gal tank
A binary compound created by reaction of an unknown element E and oxygen contains 56.05% E and 43.95% O by mass. If the formula of the compound is E2O5, calculate the atomic mass of E.
Answer:The atomic mass of E is 51
Explanation:Please see attachment for explanation
One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titrating a sample of silver nitrate solution. Any chloride anions in solution will combine with the silver cations to produce bright white silver chloride precipitate.
Suppose an EPA chemist tests a Image for One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titratin sample of groundwater known to be contaminated with nickel(II) chloride, which would react with silver nitrate solution like this:
Image for One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titratin(aq) Image for One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titratinImage for One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titratin(aq) Image for One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titratinImage for One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titratin(s) Image for One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titratinImage for One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titratin(aq)
The chemist adds Image for One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titratinM silver nitrate solution to the sample until silver chloride stops forming. She then washes, dries, and weighs the precipitate. She finds she has collected Image for One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titratin of silver chloride.
Calculate the concentration of nickel(II) chloride contaminant in the original groundwater sample. Round your answer to significant digits.
Answer:
5.0x10⁻⁵ M
Explanation:
It seems the question is incomplete, however this is the data that has been found in a web search:
" One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titrating a sample of silver nitrate solution. Any chloride anions in solution will combine with the silver cations to produce bright white silver chloride precipitate. Suppose a EPA chemist tests a 250 mL sample of groundwater known to be contaminated with nickel(II) chloride, which would react with silver nitrate solution like this:
NiCl₂ + 2AgNO₃ → 2AgCl + Ni(NO₃)₂
The chemist adds 50 mM silver nitrate solution to the sample until silver chloride stops forming. She then washes, dries, and weighs the precipitate. She finds she has collected 3.6 mg of silver chloride. Calculate the concentration of nickel(II) chloride contaminant in the original groundwater sample. Round your answer to 2 significant digits. "
Keep in mind that while the process is the same, if the values in your question are different, then your answer will be different as well.
First we calculate the moles of nickel chloride found in the 250 mL sample:
3.6 mg AgCl ÷ 143.32 mg/mmol * [tex]\frac{1mmolNiCl_{2}}{2mmolAgCl}[/tex] = 0.0126 mmol NiCl₂Now we divide the moles by the volume to calculate the molarity:
0.0126 mmol / 250 mL = 5.0x10⁻⁵MThe density of mercury (the element) is 13.69 g/cm3. The density of Mercury (the planet) is 5.43 g/cm3. If Mercury (the planet) was made of mercury (the element) and had the same mass, what would its diameter be?
Answer:
The diameter of Mercury would be 0.735 times smaller than the actual diameter i.e., it would become 3590 km from 4879 km
Explanation:
For the sake of simplicity, let us consider Mercury spherical and uniform. The provided data shows that if the Mercury planet is purely composed of mercury then it will require less space as compared to the actual planet, due to the higher density of the mercury. The ratio of the two densities shows that the volume of Mercury would reduce 2.52 times. From the change in volume we can determine the change in diameter by taking the ratio of initial and final states, shown in the following derivation:
[tex]V=(\frac{4}{3})(\pi )(r^{3})[/tex],
Here, V is the volume and r is the radius of the Mercury.
From the ratio of initial and final states, we obtain the following relation
[tex]\frac{V_{2} }{V_{1} } = \frac{r_{2} ^{3}}{r_{1} ^{3}}[/tex]
as,
[tex]V_{2}=\frac{V_{1}}{2.52}[/tex]
so,
[tex]\frac{1}{2.52} = \frac{r_{2} ^{3}}{r_{1} ^{3}}[/tex]
[tex]r_{2}^{3}=\frac{r_{1}^{3}}{2.52}[/tex]
[tex]r_{2}= 0.735.r_{1}[/tex]
The factor will remain same for the diameter i.e.,
[tex]D_{2}= 0.735 D_{1}[/tex]
For absolute diameter of Mercury:
Actual diameter of Mercury = 4879.4 km
Hence, the diameter of Mercury, if it was made of mercury would become 3590 km.
P.S.: The element mercury first letter is kept small while the other is capped
If we find that there is a linear correlation between the concentration of carbon dioxide in our atmosphere and the globalâ temperature, does that indicate that changes in the concentration of carbon dioxide cause changes in the globalâ temperature? Choose the correct answer below.
Answer:
The answer will be that if there is a linear relationship exist between CO2 and the global temperature, then if one variable change, the other also will change correspondingly.
There are four hundred participants in the local Thanksgiving 5K race. If 51% of the participants are female, what is the ratio of female participants to male participants?
ITS FOR MATH. I ACCIDENTALLY CLICKED CHEMISTRY
Answer:
51:49 is the ratio of female participants to male participants.
Explanation:
Percentage of females in the race = 51 %
Percentage of males in the race = 100% - 51 % = 49%
Total participants in race = 400
Number of women participants = [tex]51% of 400=\frac{51}{100}\times 400=204[/tex]
Number of men participants = [tex]49% of 400=\frac{49}{100}\times 400=196[/tex]
Ratio of female participants to male participants :
[tex]\frac{204}{196}=\frac{51}{49}=51:49[/tex]
Final answer:
To determine the ratio of female to male participants in a race with 400 participants and 51% females, we calculate 204 females and 196 males, resulting in a simplified ratio of 51:49.
Explanation:
To find the ratio of female to male participants in a local Thanksgiving 5K race with four hundred participants, where 51% are female, we first calculate the number of female and male participants. Since 51% of 400 participants are female, there are 204 female participants (0.51 × 400). The remaining participants are male, which accounts for 196 participants (400 - 204).
The ratio of female to male participants can be expressed as 204:196. To simplify this ratio, we divide both numbers by their greatest common divisor, which is 4. Therefore, the simplified ratio of female to male participants is 51:49.