AP chemistryreaction in the shaft考试题
Choose one of the following for questions 1–4.
(A) There is no change in the voltage.
(B) The voltage becomes zero.
(C) The voltage increases.
(D) The voltage decreases, but stays positive.
(E) The voltage becomes negative.
The following reaction takes place in a voltaic cell.
Zn(s) + Cu2+(1 M) → Cu(s) + Zn2+(1 M)
The cell has a voltage that is measured and foundto be +1.10 V.
1. What happens to the voltage when a saturatedZnSO4 solution is added to the zinc compartmentof the cell?
2. What happens to the cell voltage when thecopper electrode is made smaller?
3. What happens to the cell voltage when thesalt bridge is filled with deionized water insteadof 1 M KNO3?
4. What happens to the cell voltage after the cell hasoperated for 10 minutes?
Questions 5–8 refer to the following aqueoussolutions. All concentrations are 1 M.
(A) H2C2O4(oxalic acid) and KHC2O4(potas-sium hydrogen oxalate)
(B) KNO3 (potassium nitrate) and HNO3(nitric acid)
(C) NH3 (ammonia) and NH4NO3 (ammoniumnitrate)
(D) C2H5NH2(ethylamine) and KOH (potas-sium hydroxide)
(E) CH3NH2(methylamine) and HC2H3O2(acetic acid)
5. The most acidic solution (lowest pH)
6. The solution with a pH nearest 7
7. A buffer with a pH> 7
8. A buffer with a pH< 7
9. An atom of 23892U undergoes radioactive decay by α emission. What is the product nuclide?
(A) 23090 Th
(B) 23490Th
(C) 23092 U
(D) 23091Pa
(E) 230238 Pu
10 . The specific rate constant, k , for radioactive beryllium-11 is 0.049 s−1. What mass of a 0.500 mg sample of beryllium-11 remains after 28 seconds?
(A) 0.250 mg
(B) 0.125 mg
(C) 0.0625 mg
(D) 0.375 mg
(E) 0.500 mg
11. H2PO4−+ H2O ↔ H3O++ HPO42−
Which species, in the above equilibrium, behaveas bases?
I. HPO42−
II. H2PO4−
III. H2O
(A) I only
(B) I and II
(C) II and III
(D) I and III
(E) III only
12. A sample of silver is to be purified by electrorefining.This will separate the silver from an impurityof gold. The impure silver is made into an electrode.Which of the following is the best way toset up the electrolytic cell?
(A) an impure silver cathode and an inert anode
(B) an impure silver cathode and a pure gold anode
(C) a pure silver cathode with an impure silveranode
(D) a pure gold cathode with an impure silver anode
(E) an impure silver cathode with a pure silveranode
13. Cycloalkanes are hydrocarbons with the general formula CnH2n. If a 0.500 g sample of any alkene is combusted in excess oxygen, how many moles of water will form?
(A) 0.50
(B) 0.072
(C) 0.036
(D) 1.0
(E) 0.018
14. The purpose of striking a match against the side of a box to light the match is
(A) to supply the free energy for the reaction
(B) to supply the activation energy for the reaction
(C) to supply the heat of reaction
(D) to supply the kinetic energy for the reaction
(E) to catalyze the reaction
15. When the concentration of H+ (aq) is doubled for the reaction H2O2 (aq) + 2 Fe2+ (aq) + 2 H+(aq) → 2Fe3+(aq) + 2H2O(g), there is no change in the reaction rate. This indicates
(A) the H+ is a spectator ion
(B) the rate-determining step does not involve H+
(C) the reaction mechanism does not involve H+
(D) the H+ is a catalyst
(E) the rate law is first order with respect to H+
16. H2O2(aq) + KIO4(aq) → KIO3(aq) + O2(g) +H2O(l)
Choose the true statement from the following list.
(A) The iodine oxidation state is reduced from+8 to +6.
(B) This is not an oxidation–reduction reaction.
(C) H2O2 behaves as a reducing agent.
(D) Hydrogen is reduced from +2 to +1.
(E) H2O2 behaves as an oxidizing agent.
17. Which of the following lists the types of radiation in the correct order of increasing penetrating power?
(A) α, γ, β
(B) β, α, γ
(C) α, β, γ
(D) β, γ, α
(E) γ, β, α
18. C(s)+ H2O(g) ↔CO(g) + H2O(g) endothermic
An equilibrium mixture of the reactants is placedin a sealed container at 150°C. The amount ofthe products may be increased by which of the following changes?
I. raising the temperature of the container
II. increasing the volume of the container
III. adding 1 mol of C(s) to the container
(A) II only
(B) I and II
(C) I only
(D) II and III
(E) III only
19. When a basic solution of KMnO4 is added to anSnCl2 solution, a brown precipitate of MnO2forms and Sn4+remains in solution. When thesame basic solution of KMnO4 is added to anNaF solution, no reaction occurs. Which of thesubstances involved in these reactions serves asthe best reducing agent?

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