chapter 9 exam
2NO2 + H2O2 → 2HNO3 a) decomposition b) combination c) single-replacement d) double-replacement
b
CO2(g) + 3H2(g) + heat = CH4(g) + H2O(g): Increase in volume of the container (pressure decrease). a) shifts to the right b) shifts to the left c) does not shift d) shifts to both the left and the right
b
CO2(g) + 3H2(g) + heat = CH4(g) + H2O(g): Some CO2 is removed. a) shifts to the right b) shifts to the left c) does not shift d) shifts to both the left and the right
b
Increasing the temperature at which a chemical reaction occurs A) will lower the activation energy. B) cause more reactant collisions to take place in a given time. C) increase disorder in the system, thus decreasing the reaction rate. D) more than one correct response E) no correct response
b
Most reactions are carried out in liquid solution or in the gaseous phase because in such situations A) activation energies are higher. B) it is easier for reactants to come in contact with each other. C) kinetic energies of reactants are lower. D) products are less apt to decompose.
b
Oxidation number of Fe in Fe2O3 a) +2 b) +3 c) +4 d) +6
b
Oxidation number of Mn in Mn3+ a) +2 b) +3 c) +4 d) +6
b
Which of the following statements about activation energy is correct? A) It is the same for all reactions. B) It is low for reactions that take place rapidly. C) It is the maximum energy a reacting molecule may possess. D) more than one correct response E) no correct response
b
which of the following general reaction types is characterized by there being a single reactant? A) combination B) decomposition C) single-replacement D) double-replacement
b
For a collision between molecules to result in reaction, the molecules must possess a certain minimum energy and A) exchange electrons. B) interact with a catalyst for at least 1 second. C) have a favorable orientation relative to each other when they collide. D) more than one correct response E) no correct response
c
Which of the following statements concerning redox reactions is incorrect? A) the reducing agent is the substance oxidized B) the oxidizing agent is the substance reduced C) the reducing agent gains electrons D) the substance oxidized loses electrons
c
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c
According to Le Chatelier's principle, which of the following changes will shift the position of the equilibrium to the left for the reaction N2(g) + 3H2(g) = 2NH3 (g) A) double the concentration of N2 B) halve the concentration of NH3 C) double the concentration of H2 D) double the temperature
d
According to Le Chatelier's principle, which of the following effects will occur if NH3 is removed from an equilibrium mixture governed by the equation: N2(g) + 3H2(g) = 2NH3(g) + heat A) Concentration of N2 will increase. B) Heat will be generated. C) Concentration of H2 will decrease. D) more than one correct response E) no correct response
d
CO2 and H2 are allowed to react until an equilibrium is established as follows: CO2 (g) + H2 (g) = H2O (g) + CO (g) What will be the effect on the equilibrium of removing CO from the equilibrium mixture? A) there will be more reactants than products B) H2 concentration will double C) CO and CO2 concentrations will triple D) H2 concentration will decrease and H2O concentration will increase
d
CO2 and H2 are allowed to react until equilibrium is established as follows: CO2(g) + H2(g)= H2O(g) + CO(g) Which of the following changes will cause the equilibrium position to shift to the right? A) increase in the concentration of H2 B) decrease in the concentration of CO C) decrease in the concentration of CO2 D) more than one correct response E) no correct response
d
KCN+HCl→HCN+KCl a) decomposition b) combination c) single-replacement d) double-replacement
d
Oxidation number of Cr in Cr2O72- a) +2 b) +3 c) +4 d) +6
d
Oxidation number of S in H2SO4 a) +2 b) +3 c) +4 d) +6
d
The characterizations on the left pertain to the following redox equation: SO2 +NO2 →SO3 +NO: Oxidizing agent a) SO2 b) SO3 c) NO d) NO2
d
The characterizations on the left pertain to the following redox equation: SO2 +NO2 →SO3 +NO: Substance reduced a) SO2 b) SO3 c) NO d) NO2
d
What is the change in oxidation number for manganese in the redox reaction 2Mn2O3 + 3C → 4Mn + 3CO2 A) +4to-4 B) +2to0 C) +3to+4 D) +3to0
d
Which of the following changes will decrease reaction rate for the chemical reaction 2CO + O2 → 2CO2 A) adding some O2 to the reaction mixture B) tripling the temperature of the reaction mixture C) adding a catalyst to the reaction mixture D) removing half of the CO from the reaction mixture
d
Which of the following reactions is a non-redox reaction? A) CaCO3 → CaO + CO2 B) 2KClO3 → 2KCl + 3 O2 C) SO3 + H2O → H2SO4 D) more than one correct response E) no correct response
d
4PH3 + Ni(CO)4 → 4CO + Ni(PH3)4 a) decomposition b) combination c) single-replacement d) double-replacement
c
CO2(g) + 3H2(g) + heat = CH4(g) + H2O(g): A catalyst is added. a) shifts to the right b) shifts to the left c) does not shift d) shifts to both the left and the right
c
Catalysts are correctly characterized by each of the following statements except one. The exception is A) they can be either solids, liquids or gases. B) they lower the activation energy for a reaction. C) they do not actively participate in a reaction. D) they are not consumed in a reaction.
c
Chemical equilibrium is reached in a system when A) complete conversion of reactants to products has occurred. B) reactant and product concentrations are equal. C) reactants are being consumed at the same rate they are being produced. D) more than one correct response E) no correct response
c
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e
In the redox reaction 4Fe + 3 O2 + 12HCl → 4FeCl3 + 6H2O A) HCl is the reducing agent. B) O2 is the substance oxidized. C) Fe undergoes an oxidation number decrease of 3 units per atom. D) more than one correct response E) no correct response
e
In a redox reaction, the oxidizing agent is the substance A) that is oxidized. B) that loses electrons. C) that contains an element that undergoes a decrease in oxidation number. D) more than one correct response E) no correct response
c
In the redox reaction 2FeCl3 + PbI2 → 2FeCl2 + PbI4 A) PbI2 is the oxidizing agent B) FeCl3 is the substance oxidized C) Pb undergoes an oxidation number change of 2 units D) Fe undergoes an oxidation number change of 6 units
c
Whether a reaction is exothermic or endothermic is determined by A) the activation energy. B) the physical state of the reactants. C) how reactant and product potential energies compare. D) whether a catalyst is present.
c
Which of the following reactions is a nonredox decomposition reaction? A) 2CuO → 2Cu + O2 B) 2KClO3 → 2KCl + 3 O2 C) CaCO3 → CaO + CO2 D) SO2 + H2O → H2SO3
c
Which element is oxidized in the following redox reaction? 2H2S+O2 →2H2O+S A) sulfur in H2S B) hydrogen in H2S C) oxygen in O2 D) oxygen in H2O
a
Which of the following statements concerning oxidation and reduction is correct? A) They cannot occur independently of each other. B) They accompany all chemical changes. C) They describe, respectively, the gain and loss of electrons. D) more than one correct response E) no correct response
a
Which substance functions as a reducing agent in the following redox reaction? CH4 +2O2 →CO2 +2H2O A) CH4 B) O2 C) CO2 D) H2O
a
CO2(g) + 3H2(g) + heat = CH4(g) + H2O(g): Temperature is decreased a) shifts to the right b) shifts to the left c) does not shift d) shifts to both the left and the right
b
In which of the following sequences of sulfur-containing ions are the ions arranged in order of decreasing oxidation number for S? A) SO32-, SO42-, S2- B) SO42-, S2O32-, S2- C) S2O32-, SO32-, SO42- D) more than one correct response E) no correct response
b
CO2(g) + 3H2(g) + heat = CH4(g) + H2O(g): Some H2 is added. a) shifts to the right b) shifts to the left c) does not shift d) shifts to both the left and the right
a
Combustion reactions are characterized by A) oxygen always being one of the reactants. B) water always being one of the products. C) carbon dioxide always being one of the products. D) both reactants always being elements.
a
For a system at chemical equilibrium, A) forward and reverse reaction rates are equal. B) forward and reverse reaction rates are zero. C) reactant and product concentrations are equal. D) reactant and product concentrations are zero.
a
K2CO3 → K2O + CO2 a) decomposition b) combination c) single-replacement d) double-replacement
a
The characterizations on the left pertain to the following redox equation: SO2 +NO2 →SO3 +NO: Reducing agent a) SO2 b) SO3 c) NO d) NO2
a
The characterizations on the left pertain to the following redox equation: SO2 +NO2 →SO3 +NO: Substance oxidized a) SO2 b) SO3 c) NO d) NO2
a
The characterizations on the left pertain to the following redox equation: SO2 +NO2 →SO3 +NO: Substance which loses electrons a) SO2 b) SO3 c) NO d) NO2
a
The proper assignment of oxidation numbers to the elements in the compound LiN O3 would be A) +1 for Li, +5 for N and -2 for O B) +1 for Li, +5 for N and -6 for O C) +1 for Li, +1 for N and -2 for O D) +2 for Li, +4 for N and -6 for O
a
In which of the following compounds does Cl have an oxidation number of +5? A) HClO B) KClO2 C) Ca(ClO3)2 D) more than one correct response E) no correct response
c
In writing an equilibrium constant expression, which of the following is incorrect? A) Concentrations are always expressed in molarities. B) Product concentrations are always placed in the numerator of the expression. C) Concentrations of pure solids and pure liquids are always placed in the denominator of the expression. D) more than one correct response E) no correct response
c
Le Chatelier's principle states that A) only exothermic reactions can reach chemical equilibrium. B) only reactions in which a catalyst is present can reach chemical equilibrium. C) if a chemical equilibrium is disturbed, the system will try and reestablish equilibrium. D) if a chemical equilibrium is disturbed, the temperature of the system will always decrease.
c
Mg+2HCl→MgCl2 +H2 a) decomposition b) combination c) single-replacement d) double-replacement
c
Oxidation number of C in KHCO3 a) +2 b) +3 c) +4 d) +6
c
The minimum combined kinetic energy reactant particles must possess in order for their collision to result in a reaction is called the A) dissociation energy. B) collision energy. C) activation energy. D) orientation energy.
c
The proper assignment of oxidation numbers to the elements in the polyatomic ion SO32- would be A) +6 for S and -6 for O B) +6 for S and -2 for O C) +4 for S and -6 for O D) +4 for S and -2 for O
d
Which of the following statements concerning types of reactions is correct? A) The reactant in a decomposition reaction must be a compound. B) The reactants in a combination reaction must be elements. C) The reactants in a single-replacement reaction could be two compounds. D) more than one correct response E) no correct response
d
