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Multiple choice questions on energy and temperature related reactions

If ΔG is negative, a reaction is spontaneous in the forward direction. A reaction that is not spontaneous at low temperature can become spontaneous at high temperature if ΔH is ________ and ΔS is ________.

a. -, -
b. +, +
c. +, 0
d. -, +
e. +, -

Which one of the following statements is true about the equilibrium constant for a reaction if ΔG° for the reaction is negative?

a. K = 1
b. K > 1
c. More information is needed.
d. K = 0
e. K < 1

Which element is oxidized in the reaction below?
Fe(CO)5(l) + 2HI(g) Fe(CO)4I2(s) + CO(g) + H2(g)

a. Fe
b. C
c. H
d. O
e. I

Which substance is the reducing agent in the reaction below?
Pb + PbO2 + 2H2SO4 2PbSO4 + 2H2O

a. H2O
b. PbO2
c. PbSO4
d. Pb
e. H2SO4

What is the oxidation state of manganese in manganese dioxide?

a. +7
b. +2
c. +1
d. +3
e. +4

What is the coefficient of the permanganate ion when the following equation is correctly balanced?
MnO4- + Br- Mn2+ + Br2 (acidic solution)

a. 3
b. 1
c. 5
d. 2
e. 4

The balanced half-reaction in which dichromate ion is reduced to chromium (III) ion is a __________ process.

a. four-electron
b. six-electron
c. two-electron
d. three-electron
e. twelve-electron

Which of the following transformations could take place at the cathode of an electrochemical cell?

-> HNO2
b. Br2 -> BrO3-
c. HSO4- -> H2SO3
d. Mn2+ _> MnO4-
e. MnO2 -> MnO4-

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Question 2

Answer is (e). For any reaction to be spontaneous free energy should be negative. So for a reaction at low to become spontaneous enthalpy should be +ve and entropy should be -ve to male free energy negative

Question 3

Answer is ...

Solution Summary

The solutions provide answers to a variety of multiple choice questions relating to spontaneous reactions, oxidization, reducing agents, etc.