Chem 2 test 1
What is the rate of production of C in the following reaction: A + B → 2 C. A) +0.5∆[C]/∆t B) +∆[C]/∆t C) +2∆[C]/∆t D) -0.5∆[C]/∆t E) -∆[C]/∆t
+0.5∆[C]/∆t
Which of the following ions will contribute most to elevating the boiling point of H₂O? A) Na⁺ B) K⁺ C) Ca²⁺ D) Fe³⁺ E) All will contribute equally
All will contribute equally
5.93 M/s
s⁻¹
FeCl₃ has a van't Hoff factor of 3.400. What is the freezing point (in °C) of an aqueous solution made with 0.4100 m FeCl₃? (Kf for water is 1.860 °C/m)
-2.593 °C
What is the freezing point, in °C, of a solution made with 1.11 mol of CHCl₃ in 530.0 g of CCl₄ (Kf = 29.8 °C/m, normal freezing point, Tf = -22.9 °C)?
-85.3 °C
Chemists graph kinetic data to determine rate constants and the order of reactions. Analyze this data. Given that k is 0.0170 M⁻¹s⁻¹ and the [A] is 0.1000 M, determine the rate for this reaction based on the rate law determined.
0.000170 Ms⁻¹
What is the molarity of a solution of a polypeptide which has an osmotic pressure of 0.267 atm at 37.0 °C?
0.01050 M
Chemists graph kinetic data to determine rate constants and the order of reactions. Analyze this data. If the slope is 0.0170 for this reaction, determine the rate constant, k, for this reaction.
0.0170 M⁻¹s⁻¹
An equilibrium is established for the reaction 2 CO(g) + MoO₂(s) ⇌ 2 CO₂(g) + Mo(s). Use the expression for Kp from part a. If at equilibrium the partial pressure of carbon monoxide is 5.21 atm and the partial pressure of the carbon dioxide is 0.717 atm, then what is the value of Kp?
0.0189
An equilibrium is established for the reaction 2 CO(g) + MoO₂(s) ⇌ 2 CO₂(g) + Mo(s). Use the expression for Kp from part a. A system which is not necessarily at equilibrium has a partial pressure of carbon monoxide of 1.67 atm and a partial pressure of carbon dioxide of 0.341 atm. What is the value of Q, the reaction quotient?
0.0418
The initial concentration of a reactant in a first order reaction is 0.860 M. What will be its concentration after 4 half-lives have passed?
0.0538 M
Convert the concentration of 0.700M Na₂SO₄ to g/mL
0.0994 g Na₂SO₄ / mL.
You have a solution which is 39.7% by mass isopropyl alcohol (MM = 60.11 g/mol) in water. The density of this solution is 0.905 g/mL. What is the mole fraction of the isopropyl alcohol in the solution?
0.165
The Henry's law constant at 25 °C for CO₂ in water is 0.035 M/atm. What is the solubility of CO₂, in molarity units, in 1.0 L of water when the partial pressure of CO₂ is 4.9 atm?
0.172 M
If the equilibrium constant of a given reaction is 3.73, what is the equilibrium constant of its reverse reaction?
0.268
How many moles of Na₂SO₄ are in a 0.140m aqueous solution that was prepared with 2.30 kg of water
0.322 mol Na₂SO₄.
What is the concentration of A after 25.7 minutes for the reaction A → Products when the initial concentration of A is 0.750 M? (k = 0.0451 M⁻¹min⁻¹)
0.401 M
A reaction has a rate law of Rate = (1.25 M⁻²s⁻¹)[A][B]². What concentration of [B] would give the reaction a rate of 0.0557 if the concentration of [A] is 0.250 M?
0.422 M
A solution is made using 94.1 g of toluene (MM = 92.13 g/mol) and 80.0 g of benzene (MM = 78.11 g/mol). What is the mole fraction of the toluene in the solution?
0.499
Two volatile substances are mixed with one another so that the solution has a vapor pressure of 125 torr. Given the information in the table below, what is the mole fraction of substance A? Substance. P° A 87 torr B 210 torr
0.69
Percent by definition is parts per hundred. % (w/w) = (mass of solute/mass of solution) x 100. For very dilute solutions, chemists will often use parts per thousand or parts per million (ppm) or parts per billion (ppb). Calculate the concentration of a solution using each of these units. The legal limit of blood alcohol limit in most states is 0.080 grams per 100.0 grams of blood. What is this concentration in parts per thousand?
0.80 ppt
How long will it take for the concentration of A to decrease from 1.25 M to 0.387 for the second order reaction A → Products? (k = 1.52 M⁻¹min⁻¹)
1.17 min
What is the molarity of an aqueous solution that contains 0.0720g C₂H₆O₂ per gram of solution. The density of the solution is 1.04 g/mL
1.21 mol C₂H₆O₂ / L solution.
When 2.63 g of a polypeptide is dissolved in 361 mL of water, the resulting solution is found to have an osmotic pressure of 0.125 atm at 37.0 °C. What is the molar mass of the polypeptide? (Assume the volume doesn't change when the polypeptide is added.)
1.48 × 10³ g/mol
How long will it take for the concentration of A to decrease from 0.500 M to 0.120 M in the first-order reaction A → B? (k = 0.800 s⁻¹)
1.78 s
Given the following reaction CO(g) + 2H₂(g) ⇌ CH₃OH(g) You have a reaction flask that contains a mixture of 0.1 M CH₃OH, 0.152M CO, and 0.250M H₂. Find the reaction quotient, Q, for this system.
10.5
For the reaction below the partial pressure of NO₂ is 0.30 atm and the partial pressure of N₂O₄ is 1.0 atm. What is the Q of the reaction? 2 NO₂ (g) ⇌ N₂O₄ (g) Kp = 0.25
11
you have a solution which is 39.7% by mass isopropyl alcohol (MM = 60.11 g/mol) in water. The density of this solution is 0.905 g/mL. What is the molality of the isopropyl alcohol in the solution?
11.0 m
A 0.520 g sample of an unknown nonelectrolyte compound is dissolved in 4.03 g of lauric acid (Kf = 3.90 °C/m). The freezing point depression is determine to be 4.20 °C. What is the molar mass of the compound?
120 g/mol
The activation energy, Ea, for a particular reaction is 19.4 kJ/mol. If the rate constant at 80 °C is 0.820 M⁻¹s⁻¹, then what is the value of the rate constant at 345 °C? (R = 8.314 J/mol • K)
13.96 M⁻¹s⁻¹
What is the osmotic pressure, in atm, of a 0.185 M solution of MgCl₂ at 37.0 °C? (assume complete dissociation).
14.1 atm
How long will it take for the concentration of A to decrease from 1.400 M to 0.757 for the zero order reaction A → Products? (k = 0.0345 M/s)
18.6 s
The equilibrium constant for the reaction 2 HF (g) ⇌ H₂ (g) + F₂ (g) is 0.190 at a particular temperature. What is the equilibrium constant for the equation ½ H₂ (g) + ½ F₂ (g) ⇌ HF (g)?
2.29
A nonvolatile solute is dissolved in benzene so that it has a mole fraction of 0.163. What is the vapor pressure of the solution in torr? (P° of benzene is 26.5 torr)
22.2 torr
At a particular temperature, the solubility of He in water is 0.080 M when the partial pressure is 1.7 atm. What partial pressure (in atm) of He would give a solubility of 1.110 M?
23.6 atm
The freezing point of pure benzene (C₆H₆) is 5.49 °C. The freezing point of a solution made using toluene (C₇H₈) in benzene is determined to be -13.0 °C. What is the molality of the toluene? (Kf benzene = 5.12 °C/m)
3.61 m
An experimental plot of ln(k) vs. 1/T is obtained in lab for a reaction. The slope of the best-fit line for the graph is -4320 K. What is the value of the activation energy for the reaction in kJ/mol?
35.9 kJ/mol
The reaction A + 2 B → C has the rate law rate = k[A][B]. By what factor does the rate of reaction increase when both [A] and [B] are doubled?
4
What is the overall reaction order for the following rate law: Rate = k[A][B][C]²
4
A reaction mechanism has the following proposed elementary steps: Step 1: A ⇌ B + C Step 2: A + B → D Step 3: 2 A + D → C + E Which of the following equations would represent the overall reaction for this mechanism? A) A + B + D → C + E B) 4 A + B + D → B + 2C + D + E C) 2 A + B → 2 C + E D) 4 A → 2 C + E
4 A → 2 C + E
The activation energy Ea for a particular reaction is 42.2 kJ/mol. How much faster is the reaction at 343 K than at 313 K? (R = 8.314 J/mol • K)
4.13
Consider the following reactions: A ⇌ B, K₁=8.59 A ⇌ C, K₂=2.00 What is K for the reaction C ⇌ B?
4.30
The half-life for the zero order reaction A → Products is 276 s. What is the value of the rate constant for the reaction if the initial concentration of A is 0.249?
4.51 × 10⁻⁴ M/s
Using the information in the table, the value of the rate constant for the reaction 2 A(g) + B(g) → C(g) + D(g) is A) 4.6 s⁻¹ B) 0.046 s⁻¹ C) 1.84 M⁻¹s⁻¹ D) 115 M⁻²s⁻¹ E) 0.42 s⁻¹
4.6 s⁻¹
For the reaction 3 A + 4 B → 2 C + D, what is the magnitude of the rate of change for [C] when [D] is increasing at 2.7 M/min?
5.4 M/min
What is the absolute magnitude of the rate of change for [NH₃] if the rate of change for [H₂] is 8.90 M/s in the reaction 2 NH₃(g) → N₂(g) + 3 H₂(g)?
5.93 M/s
you have a solution which is 39.7% by mass isopropyl alcohol (MM = 60.11 g/mol) in water. The density of this solution is 0.905 g/mL. What is the molarity of the isopropyl alcohol in the solution?
5.98 M
If Kp = 7.3 × 10⁻⁶ for the reaction below at 400.0 K, then what is the value of Kc? (R = 0.08314 L･bar/mol･K.) 2 NBr₃ (g) ⇌ N₂ (g) + 3 Br₂ (g)
6.6 × 10⁻⁹
The activation energy, Ea, for a particular reaction is 13.6 kJ/mol. If the rate constant at 754 °C is 24.5/min, at what temperature (in °C) will the rate constant be 20.3/min? (R = 8.314 J/mol • K)
646 °C
Percent by definition is parts per hundred. % (w/w) = (mass of solute/mass of solution) x 100. For very dilute solutions, chemists will often use parts per thousand or parts per million (ppm) or parts per billion (ppb). Calculate the concentration of a solution using each of these units. The legal limit of blood alcohol limit in most states is 0.080 grams per 100.0 grams of blood. What is this concentration in parts per million?
800 ppm
Percent by definition is parts per hundred. % (w/w) = (mass of solute/mass of solution) x 100. For very dilute solutions, chemists will often use parts per thousand or parts per million (ppm) or parts per billion (ppb). Calculate the concentration of a solution using each of these units. The legal limit of blood alcohol limit in most states is 0.080 grams per 100.0 grams of blood. What is this concentration in parts per billion?
800000 ppb
The conversion of CO(g) to CO₂(g) is sped up by introducing CO(g) to solid platinum. This makes platinum: A) A homogeneous inhibitor B) A heterogeneous inhibitor C) A homogeneous catalyst D) A heterogeneous catalyst E) None of the above
A heterogeneous catalyst
Consider the following two reactions occurring in the same vessel: A ⇌ B, K=0.01 A ⇌ C, K=0.02 What will there be most of in solution? A) A B) B C) C D) They'll all exist in equal amounts.
A) A
Which of the following will decrease the rate of a reaction? A) Removing a catalyst from the reaction. B) Decreasing the temperature. C) Decreasing the surface area of a solid reactant. D) Decreasing the concentration of the reactants. E) All of these will decrease the rate of a reaction.
All of these will decrease the rate of a reaction.
A reaction mechanism has the following proposed elementary steps: Step 1: A ⇌ B + C Step 2: A + B → D Step 3: 2 A + D → C + E The overall reaction is 4 A → 2 C + E. Which species are intermediates in this reaction? A) B and C B) B C) B and D D) D E) C and D
B and D
Based only on their intermolecular forces, which of the following solutions would be immiscible in one another? A) CH₃CH₂CH₂CH₂CH₃ and CH₃CH₂CH₂OCH₃ B) CH₃CH₂CH₂CH₂CH₃ and CH₃CH₂CH₃ C) CH₃CH₂CH₂OCH₃ and CH₃CH₂CH₂CH₂OH D) CH₃CH₂CH₂OH and CH₃OH
CH₃CH₂CH₂CH₂CH₃ and CH₃CH₂CH₂OCH₃
Based only on intermolecular forces, which of the following pairs of molecules would be predicted to form an endothermic solution? A) CH₃CH₂CH₂CH₂CH₃ and CH₃CH₂CH₂OCH₃ B) CH₃CH₂CH₂CH₂CH₃ and CH₃CH₂CH₂CH₃ C) CH₃CH₂CH₂OCH₃ and CH₃CH₂CH₂CH₂OH D) CH₃CH₂CH₂CH₂CH₃ and CH₃CH₂CH₂NH₂
CH₃CH₂CH₂OCH₃ and CH₃CH₂CH₂CH₂OH
Based only on their intermolecular forces, which of the following pairs of molecules would be soluble in one another? A) CH₃CH₂CH₂CH₂CH₃ and CH₃OH B) CH₃CH₂CH₂OCH₃ and CH₃CH₂CH₃ C) CH₃CH₂CH₂OCH₃ and CH₃CH₂CH₂CH₂OH D) CH₃CH₂CH₂CH₂CH₃ and CH₃CH₂CH₂NH₂
CH₃CH₂CH₂OCH₃ and CH₃CH₂CH₂CH₂OH
You have a solution which is 39.7% by mass isopropyl alcohol (MM = 60.11 g/mol) in water. The density of this solution is 0.905 g/mL. What intermolecular forces are shared between isopropyl alcohol and water? A) Dipole-Dipole forces only B) Dispersion and Dipole-Dipole forces C) Dispersion, Dipole-Dipole, and Hydrogen Bonding D) Dispersion forces only E) Dispersion forces and Hydrogen Bonding
Dispersion, Dipole-Dipole, and Hydrogen Bonding
Which of the following would become more soluble in water at higher pressure? A) NaOH (s) B) N₂ (g) C) C₆H₆ (l) D) C₆H₁₂O₆ (s)
N₂ (g)
Which of the following statements is true about the solubility of N₂ (g) in CH₃OH (l)? A) N₂ will be more soluble at higher temperatures. B) The solubility of N₂ will be independent of temperature. C) N₂ will not be soluble at all in CH₃OH. D) N₂ will be more soluble at higher partial pressures of N₂.
N₂ will be more soluble at higher partial pressures of N₂.
What is the rate law for the reaction A → B if the rate constant, k, is 0.25 M⁻¹ s⁻¹ at 75°C? A) Rate = 0.25 M⁻¹ s⁻¹[A] B) Rate = 0.25 M⁻¹ s⁻¹[A]² C) Rate = 4.0 M⁻¹ s⁻¹[A]² D) Rate = 0.25 M⁻¹ s⁻¹[B] E) Rate = 0.25 M⁻¹ s⁻¹[B]²
Rate = 0.25 M⁻¹ s⁻¹[A]²
A reaction mechanism has the following proposed elementary steps: Step 1: A ⇌ B + C Step 2: A + B → D Step 3: 2 A + D → C + E If Step 1 is the rate-limiting step, what would the proposed rate law for this mechanism be? A) Rate = k[A] B) Rate = k[A]²[D] C) Rate = k[A]⁴ D) Rate = k[A][B] E) Rate = k[A]²
Rate = k[A]
A reaction mechanism has the following proposed elementary steps: Step 1: A ⇌ B + C Step 2: A + B → D Step 3: 2 A + D → C + E Which of the following would be the correct elementary rate law for Step 1? A) Rate = k[A] B) Rate = k[A][B] C) Rate = k[A][B][C] D) Rate = k[B][C]
Rate = k[A]
A reaction mechanism has the following proposed elementary steps: Step 1: A ⇌ B + C Step 2: A + B → D Step 3: 2 A + D → C + E Which of the following would be the correct elementary rate law for Step 2? A) Rate = k[A] B) Rate = k[A][B] C) Rate = k[A][B][D] D) Rate = k[A][D]
Rate = k[A][B]
Using the information in the table, the rate law for the reaction A(g) + 3 B(g) → C(g) + 2 D(g) is A) Rate = k[A][B]³ B) Rate = k[B] C) Rate = k[A][B] D) Rate = k[A][B]²
Rate = k[A][B]
A reaction mechanism has the following proposed elementary steps: Step 1: A ⇌ B + C Step 2: A + B → D Step 3: 2 A + D → C + E If Step 2 is the rate-limiting step, what would the proposed rate law for this mechanism be? A) Rate = k[A] B) Rate = k[A]²[D] C) Rate = k[A]⁴ D) Rate = k[A][B] E) Rate = k[A]²/[C]
Rate = k[A]²/[C]
A reaction mechanism has the following proposed elementary steps: Step 1: A ⇌ B + C Step 2: A + B → D Step 3: 2 A + D → C + E Which of the following would be the correct elementary rate law for Step 3? A) Rate = k[A]² B) Rate = k[A]²[D] C) Rate = k[A][D] D) Rate = k[C][E]
Rate = k[A]²[D]
Which species has the greatest rate of appearance in the reaction below? 2 H₂S + O₂ → 2 S + 2 H₂O A) H₂S B) O₂ C) S D) H₂O E) S and H₂O have identical rates
S and H₂O have identical rates
If a plot of 1/[A] versus time produces a straight line with a positive slope for the reaction A → B + C, what is the order of the reaction? A) Zero B) First C) Second D) Third E) Cannot determine order from this information
Second
Which of the following is true for a reaction at equilibrium? A) The rate of the forward reaction is greater than the rate of the reverse reaction. B) The rate of the forward reaction is less than the rate of the reverse reaction. C) The rate of the forward reaction is equal to the rate of the reverse reaction. D) The rates of the forward and reverse reactions become zero because the reaction stops. E) The rates of the forward and reverse reactions can no longer be determined.
The rate of the forward reaction is equal to the rate of the reverse reaction.
For the reaction below, Q = 600. What must happen for the reaction to reach equilibrium? 2 A (g) + B (s) ⇌ 2 C (s) + D (g) Kp = 8210 A) The reaction needs to shift in the forward direction. B) The reaction needs to shift in the reverse direction. C) The reaction is already at equilibrium and no shift needs to take place. D) There is not enough information to determine how the reaction will reach equilibrium.
The reaction needs to shift in the forward direction.
Consider the following acidic equilibrium: H₂CO₃(aq) + H₂O(l) ⇌ HCO₃⁻(aq) + H₃O⁺(aq). If you add NaHCO₃ to this solution, which of the following will occur? A) The reaction quotient will decrease. B) The reaction will shift in the reverse direction. C) The equilibrium constant will increase. D) No changes to the equilibrium positions will take place.
The reaction will shift in the reverse direction.
Consider the energy diagram for a solution formed between molecules A and B. What can be said about this solution? A) The solute will be more soluble in the solvent at high temperatures. B) The solute-solute attractions are much stronger than the solvent-solvent attractions. C) The solute is insoluble in the solvent. D) The solution formed is ideal.
The solution formed is ideal
A colloid formed with liquid particles dispersed in a gas is known as a(n): A) aerosol B) emulsion C) foam D) sol E) gel
aerosol
When NO₂ dimerizes (two molecules join together to form a 'dimer') into N₂O₄, an equilibrium is reached and in the process this reaction produces heat. If you increase the temperature of the chamber in which both NO₂ and N₂O₄ reside, you would observe A) an increase in NO₂. B) an increase in N₂O₄. C) no change in concentration. D) a decrease in the reaction rate.
an increase in NO₂.
Consider the following reaction: 2 SO₂(g) + O₂(g) ⇌ 2 SO₃(g). If you decrease the volume of the reaction chamber, you would observe A) an increase in SO₂. B) an increase in O₂. C) an increase in SO₃. D) both (A) and (B). E) none of the above.
an increase in SO₃.
A supersaturated solution can be made to precipitate out by: A) Adding more solute B) Agitating the solution C) Both (A) and (B) D) None of the above
both a and b
Which of the following steps in solution formation is exothermic? A) overcoming the solute-solute intermolecular forces. B) overcoming the solvent-solute intermolecular forces. C) overcoming the solvent-solvent intermolecular forces. D) establishing the solute-solvent intermolecular forces.
establishing the solute-solvent intermolecular forces.
Soap suds would be an example of A) sol B) emulsion C) foam D) aerosol
foam
For the reaction: Mg(OH)₂ (s) ⇌ Mg²⁺ (aq) + 2 OH⁻ (aq) Adding Mg(OH)₂ will A) have no effect. B) increase the concentration of the hydroxide ions. C) decrease the concentration of the magnesium ions. D) change the value of the equilibrium constant.
have no effect.
Which of the following changes would cause the reaction below to shift in the forward direction to reestablish equilibrium? 2 NBr₃ (g) ⇌ N₂ (g) + 3 Br₂ (g) A) adding a catalyst. B) adding Ar (g). C) increasing the total volume of the container. D) adding N₂.
increasing the total volume of the container.
Consider the following reaction: CH₃COOH(aq) + H₂O(l) ⇌ CH₃COO⁻(aq) + H₃O⁺(aq). An increase in the pressure of the chamber where this reaction takes place will result in A) an increase in CH₃COOH. B) an increase in CH₃COO⁻. C) an increase in H₃O⁺. D) both (B) and (C) . E) no change.
no change.
Chemists graph kinetic data to determine rate constants and the order of reactions. Analyze this data. Assume that A is the only component involved up to the rate determining step. Based on the previous graph, choose the rate law for this reaction. A) rate = k B) rate = k[A] C) rate = k[A]² D) rate = k[A]³
rate = k[A]²
An equilibrium is established for the reaction 2 CO(g) + MoO₂(s) ⇌ 2 CO₂(g) + Mo(s). Kp = 0.0189 and Q = 0.0418. Which way does the reaction need to shift to reach equilibrium? A) forward B) reverse C) no shift is necessary, it is already at equilibrium.
reverse
Which of the following best describes what takes place during the solvation process? A) Molecules of the solute are attracted to one another more than the solvent. B) Solvent molecules surround solute molecules and pull them out into the solution. C) Molecules of the solvent are attracted to one another and exclude solute molecules. D) Solvent and solute molecules arrange themselves along a boundary.
solvent molecules surround solute molecules and pull them out into the solution.
When NaCl dissolves in water A) the Na⁺ ion will be attracted to the oxygen atom in water. B) the Cl⁻ ion will be attracted to the oxygen atom in water. C) the Na⁺ ion will chemically bind to the water molecule. D) the Cl⁻ ion will chemically bind to the water molecule.
the Na⁺ ion will be attracted to the oxygen atom in water
