Answer:
4. gives the relative number of atoms of each element per formula unit
Explanation:
An empirical formula -
It refers to the formula which determined the simplest whole - number ratio of all the atoms in a given species , is referred to as an empirical formula .
In simple terms ,
It is he smallest formula of the whole number which when multiplied by some whole number gives the actual structure of the compound .
Hence , from the given information of the question ,
The correct option for empirical formula is 4.
Final answer:
The empirical formula represents the simplest whole-number ratio of atoms of each element in a compound, distinguishing it from the molecular formula which shows the exact number of atoms.
Explanation:
An empirical formula is a representation of the relative number of atoms of each element in a chemical compound, showing the simplest whole-number ratio between the elements. It does not convey the actual numbers of atoms within a molecule but provides a simplified overview of the compound's composition. This characteristic distinguishes it from a molecular formula which details the exact number of atoms of each element present in a molecule. The empirical formula is fundamental in chemistry for understanding the basic composition of a compound and can be derived from the compound's percentage composition.
For example, the empirical formula of water (H2O) indicates that for every oxygen atom, there are two hydrogen atoms, presenting a ratio of 2:1. This reflects the simplest ratio of the atoms within the compound, regardless of how many molecules are present.
A wooden object from a prehistoric site has a carbon-14 activity of 10 cpm compared to 40 cpm for new wood. If carbon-14 has a half-life of 5730 yr, what is the age of the wood?
Answer:
The answer to your question is 11460 years
Explanation:
Data
Carbon-14 activity 10 cpm
half-life = 5730 yr
Real carbon-14 activity 40 cpm
Process
1.- Write a chart to solve this problem
Real carbon-14 40 cpm Time 0 years
After a half-life 20 cpm Time 5730 years
After a half-life 10 cpm Time 5730 years
Total time 11460 years
2.- Conclusion
The wooden object is 11460 years old.
An 8.10-g sample of was placed in an evacuated container, where it decomposed at 590°C according to the following reaction: At equilibrium the total pressure and the density of the gaseous mixture were 1.83 atm and 1.57 g/L respectively. Calculate for this reaction.
Correct question:
An 8.10-g sample of SO3 was placed in an evacuated container, where it decomposed at 590°C according to the following reaction:
SO3(g) <-----> SO2(g) + 1/2 O2 (g)
At equilibrium the total pressure and the density of the gaseous mixture were 1.83 atm and 1.57 g/L respectively. Calculate Kp for this reaction
Answer:
Kp for this reaction is 0.149atm
Explanation:
Given details
The state reaction
SO3(g) <-----> SO2(g) + 1/2 O2 (g)
Density = 1.57 g/L
Temperature = 590°C = 863K
The given mass of SO3 is 8.10g
The molar mass of SO3 is
S + 3O = {(32) + 3(16)} = 80g/mol
Numbers of mole =
Given mass/molar mass = 8.10/80
Numbers of mole of SO3 = 0.1013mol
From density = mass/volume
Volume V = 8.10/1.56 = 5.2L
Initial pressure from PV = nRT
R = Universal gas constant
R = 0.0821 atm/K/mol
P = (0.1013*0.0821*863)/5.2
P = 1.38 atm
At equilibrium
moles SO3 = 0.10 - X
moles SO2 = X
moles O2 = X/2
moles total = (0.10 - X) + X + X/2
Total mole = 0.10 + X/2
Ptot = (0.10 + X/2)*0.0821*863/5.2 = 1.83
(0.10 + X/2)* 70.8523 = 9.516
X/2 = 0.1343 -0.10 = 0.0343
X = 0.0686
At equilibrium
moles SO3 = 0.10 - X = 0.10 - 0.0686 = 0.0314
moles SO2 = X = 0.0686
moles O2 = X/2 = 0.0343
moles total = 0.10 + X/2 = 0.10 + 0.0343 = 0.1343
P(SO3) = Ptot*X(SO3) = 1.83*0.0314/0.1343 = 0.428atm
P(SO2) = 1.83*0.0686/0.1343 = 0.935atm
P(O2) = 1.83*0.0343/0.1343 = 0.467atm
Kp for this reaction is
Kp = [P(SO2)*P(O2)^1/2]/P(SO3)
Kp = {0.935*(0.467)^0.5}/0.428
Kp = 0.149atm
Choose whether the statements about oil sands are true or false. The viscosity of bitumen is about 100 times greater than the viscosity of water. Oil from oil sand deposits is only obtained by first heating the sands at high temperatures. Oil sands contain sand, water, and light crude oil.
The First 2 statements stated above were false whereas the third one is a true statement.
Explanation:
The viscosity of bitumen is about 100 times greater than the viscosity of water - FalseReason - The viscosity of bitumen is about not 100 times greater than the viscosity of water, it is actually 100, 000 times greater.
Oil from oil sand deposits is only obtained by first heating the sands at high temperatures is False.Reason- Oil from oil sand deposits is not obtained by first heating the sands at high temperatures but by using steams
Oil sands contain sand, water, and light crude oil is true.The molarity of an aqueous solution of nacl is defined as the
Answer: Number of moles of NaCl per liter of solution
Explanation: Molarity can be defined as the number of moles
of solute per liter of solution.
Therefore the molarity of an aqueous solution of NaCl is thus defined as the number of moles of NaCl per liter of solution.
In a research project, a scientist adds 0.1 mole of HCN, 0.1 mole of H3O , and 0.1mole of CN- to water to make a total volume of 1 L. Will this reaction proceed to a greater extent in the forward direction or in the reverse direction
Answer:
Reverse; since the value of Q is greater than the value of K
Explanation:
The equation for the reaction can be expressed as:
[tex]HCN + H_2 O[/tex] ⇄ [tex]H_3O^+ +CN^{-}[/tex] [tex]k_a = 6.2 * 10^ {-10[/tex]
[tex]Q = \frac{[H_3O^+][CN^-]}{[HCN]}[/tex]
[tex]Q = \frac{(0.1)(0.1)}{(0.1)}[/tex]
Q = 0.1
[tex]k_a = 6.2 * 10^ {-10[/tex]
Q > [tex]K_{a}[/tex]
If the value of Q is greater than [tex]K_{a}[/tex] Value; the reaction will definitely shift to reverse direction.
In the laboratory 6.67 g of Sr(NO3)2 is dissolved in enough water to form 0.750 L. A 0.100 L sample is withdrawn from this stock solution and titrated with a 0.0460 M solution of Na3PO4. a. What is the concentration of the Sr(NO3)2stock solution? b. Write a balanced molecular equation for the titration reaction. c. How many milliliters of the Na3PO4 solution are required to precipitate all the Sr2+ ions in the 0.100 L sample? (MM's: Sr(NO3)2 = 211.64; Na3PO4 =163.94)Name
Answer:
The answer to your question is below
Explanation:
Data
mass of Sr(NO₃)₂ = 6.67 g Final volume = 0.750 L
Sample 0.100 L
[Na₃PO₄] = 0.046 M
a) [Sr(NO₃)₂
MM = 211.64 g
211.64 g ---------------------- 1 mol
6.67 g ---------------------- x
x = (6.67 x 1) / 211.64
x = 0.032 mol
Molarity = 0.032 / 0.75
Molarity = 0.042
b)
3Sr(NO₃)₂ + 2Na₃PO₄ ⇒ Sr₃(PO₄)₂ + 6NaNO₃
Reactants Elements Products
3 Sr 3
6 N 6
6 Na 6
2 P 2
24 O 24
c)
Calculate the moles of Sr(NO₃)₂ in 100 ml or 0.1 L
Molarity = moles / volume
Moles = Molarity x volume
Moles = 0.042 x 0.1
Moles = 0.0042
3 moles of Sr(NO₃)₂ --------------- 2 moles of Na₃PO₄
0.0042 moles of Sr(NO₃)₂ -------- x
x = (0.0042 x 2) / 3
x = 0.0028 moles of Na₃PO₄
Molarity = moles / volume
Volume = moles / Molarity
Volume = 0.0028 / 0.046
Volume = 0.060 L or 60.9 mL
The volume of a sample of chlorine gas is 8.00 liters at 45.0 degrees Celsius and 0.966 atm. How many moles of chlorine are present in the sample? R = 0.0821 (atm)(L)(mol-1)(K-1)
Answer:
Number of moles of Cl₂ = 0.3 mol
Explanation:
Given data:
Number of moles of Cl₂ = ?
Pressure = 0.966 atm
Volume = 8.00 L
Temperature = 45°C
Solution:
The given problem will be solve by using general gas equation, which is,
PV = nRT
R = general gas constant (0.0821 atm.L/mol.K)
Now we will convert the °C into K.
Temperature = 45+ 273 = 318 K
Now we will put the values in formula.
n = PV/RT
n = 0.966 atm × 8.00 L / 318 K ×0.0821 atm.L/mol.K
n = 7.728/26.1078 /mol
n = 0.3 mol
Identify the number of bonding pairs and lone pairs of electrons in carbon dioxide. a) 2 bonding pairs and 4 lone pair b) 4 bonding pairs and 2 lone pairs c) 4 bonding pairs and 4 lone pairs d) 2 bonding pairs and 2 lone pairs e) 4 bonding pairs and 1 lone pair
Final answer:
Carbon dioxide (CO₂) consists of two oxygen atoms bonded to a central carbon atom. Each oxygen atom forms a double bond with the carbon atom. The double bond consists of two bonding pairs of electrons. Therefore, carbon dioxide has 2 bonding pairs and 0 lone pairs of electrons.
Explanation:
Carbon dioxide (CO₂) consists of two oxygen atoms bonded to a central carbon atom. Each oxygen atom forms a double bond with the carbon atom. The double bond consists of two bonding pairs of electrons. Therefore, carbon dioxide has 2 bonding pairs and 0 lone pairs of electrons. The correct option is d) 2 bonding pairs and 2 lone pairs.
The correct option is b. 4 bonding pairs and 2 lone pairs.
To determine the number of bonding pairs and lone pairs in carbon dioxide (CO2), we need to consider the Lewis structure of the molecule. Carbon dioxide has a total of 16 valence electrons, 4 from the carbon atom and 6 from each of the two oxygen atoms.
In the Lewis structure of CO2, the carbon atom is double-bonded to each oxygen atom. Each double bond consists of one sigma (σ) bond and one pi (π) bond. Since there are two double bonds, there are a total of 4 bonding pairs of electrons (2 sigma bonds and 2 pi bonds).
The Lewis structure of CO2 is as follows:
O=C=O
Here, the carbon atom has no lone pairs, as it forms double bonds with both oxygen atoms. Each oxygen atom has 2 lone pairs of electrons, but since we are asked about the entire CO2 molecule, we consider the lone pairs on both oxygen atoms together. Therefore, there are 2 lone pairs in total for the CO2 molecule.
In summary, carbon dioxide has 4 bonding pairs of electrons (from the 2 double bonds) and 2 lone pairs of electrons (1 on each oxygen atom). This matches option b.
The Na /K pump generates a membrane potential across the plasma membrane (PM) of the cell by transporting Na and K across the PM. The action of this pump results in the cell having a slightly ____________ charge inside the cell compared to the extracellular space.
Answer:
NEGATIVE CHARGE can best fill in the gap
Explanation:
The Na /K pump functions to maintain resting potential so that the cells will be kept in a state of a low concentration of sodium ions and high levels of potassium ions within the cell.
The processes of Na - K pump illustrates active transport since it moves Na+ and K+ ions against their concentration gradient. The energy required is supplied by the breakdown of ATP (adenosine triphosphate) to ADP (adenosine diphosphate). In nerve cells the pump is used to generate gradients of both sodium and potassium ions.
How does the sodium-potassium pump contribute to the net negative charge of the interior of the cell?
The sodium-potassium pump forces out three (positive) Na+ ions for every two (positive) K+ ions it pumps in, thus the cell loses a positive charge at every cycle of the pump.
A 2.00-L glass soda bottle filled only with air is tightly capped at 25°C and 728.0 mmHg. If the bottle is placed in water at 65°C, what is the pressure in the bottle?
Answer:
The pressure in the bottle is 826 mmHg
Explanation:
In this case it is assumed that the volume of the soda bottle does not change, so it remains constant with a value of 2.00 L. Then it is possible to apply the Gay Lussac law.
This law indicates that when there is a constant volume, as the temperature increases, the gas pressure increases. And when the temperature decreases, gas pressure decreases. That is, the gas pressure is directly proportional to its temperature.
Gay-Lussac's law can be expressed mathematically as follows:
[tex]\frac{P}{T}=k[/tex]
Where P = pressure, T = temperature and K = Constant
Having a gas that is at a pressure P1 and a temperature T1, as the temperature varies to a new T2 value, then the pressure will change to P2. It is then fulfilled:
[tex]\frac{P1}{T1} =\frac{P2}{T2}[/tex]
Remember that the temperature must be in degrees Kelvin (° K) and that 0 ° C is 273.15 ° K
In this case you know:
P1= 728 mmHgT1= 25°C+273.15°K= 298.15°KP2= ?T2= 65°C+273.15°K= 338.15°KReplacing:
[tex]\frac{728 mmHg}{298.15K} =\frac{P2}{338.15K}[/tex]
Resolving you get:
[tex]\frac{728 mmHg}{298.15K} *338.15K=P2[/tex]
P2=825.67 mmHg≅826 mmHg
The pressure in the bottle is 826 mmHg
The pressure of the bottle is 825.7 mmHg
The parameters given in the question are
Pressure 1= 728 mmHg
Temperature 1= 25°C
= 25+273
T1= 298K
Temperature 2= 65°C
= 65 +273
= 338K
P1/T1= P2/T2
728/298= P2/338
Cross multiply
298 × P2= 728 × 338
298 × P2= 246,064
P2= 246,064/298
P2= 825.7
Hence the pressure in the bottle is 825.7 mmHg
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Regarding the formula Al203 which of the following is accurate
Answer:
D. The subscript 2 indicates that two atoms of aluminum are present in the substance.
Explanation:
The answer choices are:
A. The coefficient 3 indicates that there are a total of three atoms of oxygen present in the substance. B. The subscript 2 indicates that two atoms of oxygen are present in the substance. C. The chemical symbol Al indicates that oxygen is present in the substance. D. The subscript 2 indicates that two atoms of aluminum are present in the substance.Solution
The correct formula is:
[tex]Al_2O_3[/tex]
What you must know to answer this question is that the chemical formulas indicate the number of atoms of each element in the formula by placing a subscript to the right of the chemical symbol that represents the atom.
Thus, we can deal with each statement:
A. The coefficient 3 indicates that there are a total of three atoms of oxygen present in the substance.
Incorrect. 3 is not a coefficient but a subscript. Thus this option is wrong.
B. The subscript 2 indicates that two atoms of oxygen are present in the substance.
Incorrect. The subscript 2 is to the right of tha aluminum symbol, thus it does not represent the number of atoms of oxygen.
C. The chemical symbol Al indicates that oxygen is present in the substance.
Incorrect. The chemical symbol Al indicates that aluminum is present in the substance. Thus, this is wrong.
D. The subscript 2 indicates that two atoms of aluminum are present in the substance.
Correct. The subscript 2 is to the right of the symbol Al, which is the chemical symbol for aluminum. Thus, this indicates that there are two atoms of aluminum in the substance.
The combustion of glucose is represented by the following balanced equation: C6H12O6+6 O2→6 H2O+6 CO2. The reaction uses 1 gram of both C6H12O6 and O2. What is the percent yield if 0.45 g of H2O is produced? a 0.558% b 100% c 0.31% d 80%
Answer : The correct option is, (d) 80 %
Solution : Given,
Mass of [tex]C_6H_{12}O_6[/tex] = 1 g
Mass of [tex]O_2[/tex] = 1 g
Molar mass of [tex]C_6H_{12}O_6[/tex] = 180 g/mole
Molar mass of [tex]O_2[/tex] = 32 g/mole
Molar mass of [tex]H_2O[/tex] = 18 g/mole
First we have to calculate the moles of [tex]C_6H_{12}O_6[/tex] and [tex]O_2[/tex].
[tex]\text{ Moles of }C_6H_{12}O_6=\frac{\text{ Mass of }C_6H_{12}O_6}{\text{ Molar mass of }C_6H_{12}O_6}=\frac{1g}{180g/mole}=0.00555moles[/tex]
[tex]\text{ Moles of }O_2=\frac{\text{ Mass of }O_2}{\text{ Molar mass of }O_2}=\frac{1g}{32g/mole}=0.0312moles[/tex]
Now we have to calculate the limiting and excess reagent.
The balanced chemical reaction is,
[tex]C_6H_{12}O_6+6O_2\rightarrow 6H_2O+6CO_2[/tex]
From the balanced reaction we conclude that
As, 6 mole of [tex]O_2[/tex] react with 1 mole of [tex]C_6H_{12}O_6[/tex]
So, 0.0312 moles of [tex]O_2[/tex] react with [tex]\frac{0.0312}{6}=0.0052[/tex] moles of [tex]C_6H_{12}O_6[/tex]
From this we conclude that, [tex]C_6H_{12}O_6[/tex] is an excess reagent because the given moles are greater than the required moles and [tex]O_2[/tex] is a limiting reagent and it limits the formation of product.
Now we have to calculate the moles of [tex]H_2O[/tex]
From the reaction, we conclude that
As, 6 mole of [tex]O_2[/tex] react to give 6 mole of [tex]H_2O[/tex]
So, 0.0312 mole of [tex]O_2[/tex] react to give 0.0312 mole of [tex]H_2O[/tex]
Now we have to calculate the mass of [tex]H_2O[/tex]
[tex]\text{ Mass of }H_2O=\text{ Moles of }H_2O\times \text{ Molar mass of }H_2O[/tex]
[tex]\text{ Mass of }H_2O=(0.0312moles)\times (18g/mole)=0.562g[/tex]
Theoretical yield of [tex]H_2O[/tex] = 0.562 g
Experimental yield of [tex]H_2O[/tex] = 0.45 g
Now we have to calculate the percent yield of the reaction.
[tex]\% \text{ yield of reaction}=\frac{\text{ Experimental yield of }H_2O}{\text{ Theoretical yield of }H_2O}\times 100[/tex]
[tex]\% \text{ yield of reaction}=\frac{0.45g}{0.562g}\times 100=80\%[/tex]
Therefore, the percent yield of reaction is, 80 %
Answer:
The yield would D. 80%!
Explanation:
Since 1 gram of O2 only produces 0.56 g of H2O, whereas 1 g of C6H12O6 produces 0.60 g of H2O, the O2 is the limiting reagent.
when the temperature of a gas changes, it's volume decreases from 12 cm3 to 7 cm3 if the final temperature is measured to be 18°C what is the initial temperature in Kelvin units?
pls help :)
Answer:
The initial temperature is 499 K
Explanation:
Step 1: Data given
initial volume = 12 cm3 = 12 mL
Final volume = 7 cm3 = 7mL
The final temperature = 18 °C = 291 K
Step 2: Calculate the initial temperature
V1/T1 = V2/T2
⇒with V1 = the initial volume = 0.012 L
⇒with T1 = the initial volume = ?
⇒with V2 = the final volume 0.007 L
⇒with T2 = The final temperature = 291 K
0.012 / T1 = 0.007 / 291
0.012/T1 = 2.4055*10^-5
T1 = 0.012/2.4055*10^-5
T1 = 499 K
The initial temperature is 499 K
In response to action potentials arriving along the transverse tubules, the sarcoplasmic reticulum releasesA) acetylcholine.B) sodium ions.C) potassium ions.D) calcium ions.E) hydrogen ions
Answer:
Calcium ions.
Explanation:
The generation of the action potential helps in the transfer of information to the different body parts. This potential occurs to the difference in membrane potential inside and outside of the cell.
The sarcoplasmic reticulum is the homologous to the endoplasmic reticulum of the cells. The sarcoplasmic reticulum contains calcium ions in it and releases the stored calcium ions on the generation of the action potential. This calcium ion is important for the action of the actin and myosin.
Thus, the correct answer is option (D).
Which compounds will be soluble in water?
Answer:
salt
Explanation:
What mass (g) of barium iodide is contained in 188 ml of a barium iodide solution that has an iodide ion concentration of 0.532m 19.6 39.1 19,600 39,100 276
The mass of barium iodide in 188 ml of a 0.532M solution is calculated to be approximately 39.11 grams using concepts of molarity, moles, and molar mass.
Explanation:The question is asking to find out the mass of barium iodide in a solution, given a certain volume and a concentration. The question is a standard calculation involving molarity and volume. Molarity (M) is defined as the number of moles of solute per liter of solution. Therefore, you can calculate the number of moles of solute first using the formula M = n/V, where n is the number of moles and V is the volume in liters. We can convert 188 mL to liters (0.188 L) and we know the molarity is 0.532M, so the number of moles in the solution is 0.532M * 0.188 L = 0.10 moles of iodide ions. To find the mass of barium iodide, we multiply this number by the molar mass of barium iodide, which is roughly 391.136 g/mol (from barium's molar mass of 137.327 g/mol and iodine's molar mass of 253.809 g/mol). Thus, the mass of barium iodide is 0.10 moles * 391.136 g/mol = 39.11 g.
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Whch compounds is most reactive toward nucleophilic acyl substitution?
Answer:
There are five main types of acyl derivatives. Acid halides are the most reactive towards nucleophiles, followed by anhydrides, esters, and amides. Carboxylate ions are essentially unreactive towards nucleophilic substitution, since they possess no leaving group
The equation shows a --the breaking and forming of chemical bonds that leads to a change in the composition of matter. 2. In the equation, CO2 is a . 3. In the equation, C6H12O6 is a . 4. In O2, the type of bond that holds the two oxygen atoms together is a . 5. In H2O, the type of bond that holds one of the hydrogen atoms to the oxygen atom is a . 6. The number of oxygen atoms on the left side of the equation is the number of oxygen atoms on the right side.
A chemical equation is said to be balanced if the quantity of each type of atom in the reaction is the same on both the reactant and product sides. In a balanced chemical equation, the mass and the charge are both equal. Here the given equation is C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O.
This means that new products are formed due to the change in the chemical composition of the reactants.
Hence, the equation shows a chemical reaction - the breaking and forming of chemical bonds that leads to a change in the composition of matter.
1. The equation is C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O.
2. And, in the given equation CO₂ is a product.
3. In the equation, C₆H₁₂O₆ is a reactant.
4. In O₂, the type of bond that holds the two oxygen atoms together is a non-polar covalent bond.
5. In H₂O, the type of bond that holds one of the hydrogen atoms to the oxygen atom is a polar covalent bond.
6. The number of oxygen atoms on the left side of the equation is equal to the number of oxygen atoms on the right side.
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How many hours will it take for the concentration of methyl isonitrile to drop to 14.0 %% of its initial value?
This is an incomplete question, here is a complete question.
The rearrangement of methyl isonitrile (CH₃NC) to acetonitrile (CH₃NC) is a first-order reaction and has a rate constant of 5.11 × 10⁻⁵ s⁻¹ at 472 K. If the initial concentration of CH₃NC is 3.00 × 10⁻² M :
How many hours will it take for the concentration of methyl isonitrile to drop to 14.0 % of its initial value?
Answer : The time taken will be, 10.7 hours
Explanation :
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant = [tex]5.11\times 10^{-5}s^{-1}[/tex]
t = time passed by the sample = ?
a = let initial amount of the reactant = 100
a - x = amount left after decay process = 14 % of 100 = 14
Now put all the given values in above equation, we get
[tex]t=\frac{2.303}{5.11\times 10^{-5}}\log\frac{100}{14}[/tex]
[tex]t=38482.72s=\frac{38482.72}{3600}=10.7hr[/tex]
Therefore, the time taken will be, 10.7 hours
The carbocation electrophile in a friedel-crafts reaction can be generated in ways other than by reaction of an alkyl chloride with alcl3.give an example
Answer: iron (II) Chloride can be used instead of AlCl3
Explanation:
Friedel–Crafts alkylation reaction involves the introduction of alkyl group in an aromatic ring with an alkyl halide using a strong Lewis acid, such as aluminium chloride, ferric chloride, or other MXn reagent, as catalyst.
The function of AlCl3 or fecl3 in Friedel-Craft reaction, is to produce electrophile, which later adds to benzene ring. This electrophilic aromatic substitution allows the synthesis of monoacylated products from the reaction between arenes and acyl chlorides or anhydrides. The products are deactivated and do not undergo a second substitution. Normally, a stoichiometric amount of the Lewis acid catalyst is required for both the substrate and the product form complexes.
AlCl3 or fecl3 (and other Lewis acids like it) will coordinate to halogens, and facilitate the breaking of these bonds. In doing so, it increases the electrophilic nature of its binding partner, making it much more reactive as to complete the reaction.
Calculate the pH after 0.018 mole of HCl is added to 1.00 L of each of the four solutions. (Assume that all solutions are at 25°C.) (a) 0.129 M acetic acid (HC2H3O2, Ka = 1.8 ✕ 10−5) (b) 0.129 M sodium acetate (NaC2H3O2) (c) pure H2O (d) 0.129 M HC2H3O2 and 0.129 M NaC2H3O2
Explanation:
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When we think about the carbon cycle and human activities, it is important to differentiate between facts and hypotheses. Which of the following is NOT a fact, but is a hypothesis? A. The amount of carbon dioxide in the atmosphere has increased since 1950. B. Increasing atmospheric carbon dioxide will cause mean global temperature to increase by 2 degrees Celsius over the next century. C. The burning of fossil fuels contributes substantially to the ongoing rise of atmospheric CO2. D. In the past, atmospheric CO2 levels reached levels higher than those observed today.
Answer:
B. Increasing atmospheric carbon dioxide will cause mean global temperature to increase by 2 degrees Celsius over the next century.
Explanation:
By definition, a hypothesis is a tentative statement or prediction with little or no experimental test. Hypotheses are always formulated such that they can be rejected if experimental findings are against them.
Hypotheses are predictive and as such, the tone is often in future tense.
From the available options, only option B sound predictive of what might happen in the future.
Hence, the correct option is B.
The overall energy involved in the formation of CsCl from Cs(s) and Cl2(g) is −443 kJ mol−1. Given the following information: heat of sublimation for Cs is +76 kJ mol−1, bond dissociation energy for 12Cl2 is +121 kJ mol−1, Ei1 for Cs is +376 kJ mol−1, and Eea for Cl(g) is 349 kJ mol−1. what is the magnitude of the lattice energy for CsCl?
Explanation:
It is given that total energy is -443 kJ/mol and formula to calculate the lattice energy is as follows.
Total energy = heat of sublimation + bond dissociation energies + ionization energy for Cs + EA of [tex]Cl^{-}[/tex] + lattice energy
-443 kJ/mol = 76 + 121 + 376 - 349 + Lattice energy
Lattice energy = (-443 - 76 -121 - 376 + 349) kJ
Lattice energy = -667 kJ
Therefore, we can conclude that -667 kJ is the magnitude of the lattice energy for CsCl.
The number of substrate molecules converted to product in a given unit of time by a single enzyme molecule at saturation is referred to as the: dissociation constant maximum velocity turnover number Michaelis constant
The turnover number refers to the number of substrate molecules converted to product per unit time by a single enzyme molecule at saturation. The Michaelis constant (Km) indicates substrate concentration for half-maximal enzyme activity, and the maximum velocity (Vmax) is reached when enzyme active sites are saturated.
The number of substrate molecules converted to product in a given unit of time by a single enzyme molecule at saturation is referred to as the turnover number, also known as kcat. This measure of enzymatic activity provides a direct indication of the active site's catalytic efficiency within the enzyme's turnover rate.
In contrast, the Michaelis constant (Km) represents the substrate concentration at which the enzyme achieves half of its maximum reaction rate, or Vmax/2. This constant is used to determine the enzyme's affinity for a substrate, with a low Km indicating a high affinity, and vice versa.
When an enzyme operates in an environment with a high concentration of substrate, it will eventually reach a point where every active site is saturated with substrate -- this is the maximum velocity (Vmax) of the reaction. The Vmax is dependent on both the speed of the enzyme and the total number of enzyme molecules available.
The relationship between Vmax, Km, and substrate concentration ([S]) is described by the Michaelis-Menten equation, which is fundamental in the study of enzyme kinetics.
hich of the following is TRUE? Group of answer choices A neutral solution does not contain any H3O+ or OH- A neutral solution contains [H2O] = [H3O⁺] A basic solution has [OH⁻] > [H3O⁺] An acidic solution has [H3O⁺] > [H2O] A basic solution does not contain H3O+
Answer:
a basic solution has [OH-] > [H3O+]
Precipitation reactions and ionic equations
(look at attachment)
Answer:
Net ionic equation: 2OH⁻(aq) + Fe²⁺(aq) → Fe(OH)₂(s)
Net ionic equation: 2K⁺(aq) + CH₃COO⁻ (aq) + 2Na⁺(aq) + S⁻²(aq) → NO REACTION
Net ionic equation: CO₃⁻²(aq) + Pb⁺²(aq) → PbCO₃(s)
Explanation:
a. Solutions of calcium hydroxide and Iron (II) chloride are mixed:
We identify the reactants:
Ca(OH)₂ , FeCl₂
In excess, the Fe(OH)₂ can make precipitate
Salts from chlorides with elements from group II are soluble.
The reaction is: Ca(OH)₂(aq) + FeCl₂(aq) → Fe(OH)₂(s) + CaCl₂(aq)
Ca(OH)₂(aq) + FeCl₂(aq) → Fe(OH)₂(s) + CaCl₂(aq)
We dissociate the compounds, except for the solid
Ca²⁺(aq) + 2OH⁻(aq) + Fe²⁺(aq) + 2Cl⁻(aq) → Fe(OH)₂(s) + Ca²⁺ + 2Cl⁻(aq)
Net ionic equation: 2OH⁻(aq) + Fe²⁺(aq) → Fe(OH)₂(s)
b. Solutions of potassium acetate and sodium sulfide are mixed:
The reactants are: KCH₃COOH and Na₂S
In this case there are no precipitates, because all the salts are soluble
We make the complete reaction:
2KCH₃COO (aq) + Na₂S(aq) → K₂S(aq) + 2NaCH₃COO (aq)
Net ionic equation is:
2K⁺(aq) + CH₃COO⁻ (aq) + 2Na⁺(aq) + S⁻²(aq) → 2K⁺(aq) + S⁻²(aq) + 2Na⁺(aq) + CH₃COO⁻ (aq)
c. Solutions of ammonium carbonate and lead(II) nitrate are mixed:
In this case, the reactants are: (NH₄)₂CO₃ and Pb(NO₃)₂
All salts from nitrate are soluble.
Carbonate makes a precipitate when it bonds Pb.
The complete reaction is:
(NH₄)₂CO₃(aq) + Pb(NO₃)₂(aq) → PbCO₃(s) + 2NH₄NO₃(aq)
We dissociate all of the compounds, except for the solid in order to make the net ionic equation:
2NH₄⁺(aq) +CO₃⁻²(aq) + Pb⁺²(aq) +2NO₃⁻(aq) → PbCO₃(s) + 2NH₄⁺ (aq) + 2NO₃⁻(aq)
The net ionic equation is: CO₃⁻²(aq) + Pb⁺²(aq) → PbCO₃(s)
The ions that are repeated, are called spectators ions. We all cancel them.
The pressure of a gas changes from 120kPa to 50kPa. The volume changes from 45L to 40L. If the initial temperature is 81°C, what is the final temperature in Kelvin units?
Answer:
The final temperature is 131 K
Explanation:
Step 1: Data given
The initial pressure = 120 kPa = 1.18431 atm
The final pressure = 50 kPa = 0.493462 atm
The initial volume = 45 L
The final volume = 40 L
The initial temperature = 81 °C = 354 K
Step 2: Calculate the final temperature
(P1*V1)/T1 = (P2*V2)/T2
⇒with P1 = the initial pressure = 1.18431 atm
⇒with V1 = the initial volume = 45 L
⇒with T1 = the initial temperature = 354 K
⇒with P2 = the final pressure = 0.493462 atm
⇒with V2 = the final volume = 40 L
⇒with T2 = the final temperature = ?
(1.18431 * 45)/354 = (0.493462*40)/T2
0.15054788 = 19.73848/T2
T2 = 19.73848/0.15054788
T2 = 131 K
The final temperature is 131 K
Final answer:
To determine the final temperature of a gas with given initial and final pressures and volumes, one applies the combined gas law. After converting the initial Celsius temperature to Kelvin, the final temperature is calculated to be 262.33K.
Explanation:
The problem at hand involves the application of the combined gas law, which allows us to calculate changes in a gas's condition. This law is represented as (P1 * V1) / T1 = (P2 * V2) / T2, where P stands for pressure, V for volume, and T for temperature in Kelvin. Given that the pressure of a gas changes from 120kPa to 50kPa and its volume changes from 45L to 40L, with an initial temperature of 81°C (which is 354.15K), we can find the final temperature.
To solve, we start with the conversion of temperatures to Kelvin and then apply the formula. The rearranged formula to find the final temperature (T2) is T2 = ((P2 * V2) * T1) / (P1 * V1). By substituting the given values, T2 = ((50kPa * 40L) * 354.15K) / (120kPa * 45L), we get a final temperature of 262.33K.
HELP ASAP!!!!!!! PLEASE!!!!!!!!
The relationship between electricity and magnetism is called
a. current.
b. electromagnetism.
c. a solenoid.
d. voltage.
Answer:
b
Explanation:
A pump contains 1.5 L of air at 175 kPa. You draw back on the piston of the pump, expanding the volume until the pressure reads 45 kPa. What is the new volume of air in the pump?
Answer:
[tex]\large \boxed{\text{86.8 L}}[/tex]
Explanation:
The temperature and amount of gas are constant, so we can use Boyle’s Law.
[tex]p_{1}V_{1} = p_{2}V_{2}[/tex]
Data:
[tex]\begin{array}{rclrcl}p_{1}& =& \text{0.579 atm}\qquad & V_{1} &= & \text{150 L} \\p_{2}& =& \text{1.00 atm}\qquad & V_{2} &= & ?\\\end{array}[/tex]
Calculations:
[tex]\begin{array}{rcl}0.579 \times 150 & =& 1.00V_{2}\\86.85 & = & 1.00V_{2}\\V_{2} & = &\dfrac{86.85}{1.00}\\\\& = &\textbf{86.8}\\\end{array}\\\text{The new volume of the gas is } \large \boxed{\textbf{86.8 L}}[/tex]
A metal object with mass of 23.2 g 23.2 g is heated to 97.0 °C 97.0 °C and then transferred to an insulated container containing 90.0 g 90.0 g of water at 20.5 °C. 20.5 °C. The water temperature rises and the temperature of the metal object falls until they both reach the same final temperature of 22.6 °C. 22.6 °C. What is the specific heat of this metal object? Assume that all the heat lost by the metal object is absorbed by the water.
Answer:
The specific heat of the object [tex]C_{obj}[/tex] = 0.457 [tex]\frac{KJ}{kg K}[/tex]
Explanation:
Mass of the object [tex]m_{obj}[/tex] = 23.2 gm
Initial temperature [tex]T_{obj}[/tex] = 97 ° c
Mass of the water [tex]m_{w}[/tex] = 90 gm
Initial temperature of water [tex]T_{w}[/tex] = 20.5 ° c
Final temperature of both water & object [tex]T_{f}[/tex] = 22.6 ° c
It is given that heat lost by the object = heat gain by the water
⇒ [tex]m_{obj}[/tex] [tex]C_{obj}[/tex] ( [tex]T_{obj}[/tex] - [tex]T_{f}[/tex] ) = [tex]m_{w}[/tex] [tex]C_{w}[/tex] ( [tex]T_{f}[/tex] - [tex]T_{w}[/tex])
Put all the values in above formula we get
⇒ 23.2 × [tex]C_{obj}[/tex] ( 97 - 22.6 ) = 90 × 4.18 × ( 22.6 - 20.5 )
⇒ [tex]C_{obj}[/tex] = 0.457 [tex]\frac{KJ}{kg K}[/tex]
This is the specific heat of the object.