Question 1

Given the following steps for a target reaction:

Target Reaction: $$A + 2B \rightarrow 2C$$

Step 1: $$A + B \rightarrow D$$ ($$\Delta G_1$ = -50 kJ/$$mol)
Step 2: $$2C \rightarrow D + B$$ ($$\Delta G_2$ = +20 kJ/$$mol)

What is the $$\Delta G$$ for the target reaction?

Accepted Answer

$$\Delta G = -30 kJ/$$mol

Question 2

Which of the following best describes the standard state of a gas?

Accepted Answer

The gas at 1 atm pressure and 25°C

Question 3

Why is a reaction with only reactants and no products considered spontaneous?

Accepted Answer

Because the system is not at equilibrium and will move toward equilibrium

Question 4

Consider the sublimation of iodine: $$I_2(s$$) \rightarrow $$I_2(g$$)$$ at 25.0°C. Which condition will make $$\Delta G_{rxn}$$ more negative?

Accepted Answer

Decreasing the partial pressure of $$I_2(g$$)$$

Question 5

Assign the oxidation states for each element in $$Ca(s) + 2 H_2O(l) \rightarrow Ca(OH)_2(aq) + H_2$(g).$$

Accepted Answer

Ca: 0, H: +1, O: -2 (reactants); Ca: +2, H: +1, O: -2 (products)

Question 6

Which element has the highest priority when assigning oxidation states in compounds according to the rules?

Accepted Answer

Fluorine

Question 7

What is the oxidation state of sulfur in $$SO_4$$^{2-}$$?

Accepted Answer

+6

Question 8

Which of the following reactions is a redox reaction?

Accepted Answer

$$2H_2(g) + O_2$(g) \rightarrow 2H_2O(g)$$

Question 9

In a voltaic cell, which statement is correct?

Accepted Answer

Oxidation occurs at the anode

Question 10

Which battery notation correctly represents a cell where zinc is oxidized and copper is reduced?

Accepted Answer

$$Zn(s) | Zn$$^{2+}$$(aq) || Cu$$^{2+}$$(aq) | Cu(s)$$

Question 11

Which of the following statements about cell potential ($$E_{cell}) is $$true?

Accepted Answer

A positive $$E_{cell}$$ means the reaction is spontaneous

Question 12

In the reaction $$Zn(s) + Cu$$^{2+}$$(aq) \rightarrow Zn$$^{2+}$$(aq) + Cu(s)$$, which species is oxidized?

Accepted Answer

Zn

Question 13

Which of the following is the correct balanced half-reaction for the reduction of $$MnO_4$$^-$$ in acidic solution?

Accepted Answer

$$MnO_4^- + 8H^+ + 5e$$^- \rightarrow $$Mn^{2+} + 4H_2O$

Question 14

Which of the following statements about electrolytic cells is correct?

Accepted Answer

Electrolytic cells require an external voltage source

Question 15

If a metal has a negative standard reduction potential, what does this indicate about its behavior in acid?

Accepted Answer

It will dissolve in acid, undergoing oxidation

Question 16

Which of the following is the correct relationship between free energy and cell potential?

Accepted Answer

$$\Delta G = -nFE_{cell}$$

Question 17

A voltaic cell is constructed using nickel and manganese. If $$E^0$$_{$$Ni^{2+}/Ni$$} = -0.25$$ V and E^0$_{Mn$$^{2+}$$/Mn} = -1.18 V$$, which metal is the anode?

Accepted Answer

Manganese

Question 18

Which of the following best describes the function of a salt bridge in a voltaic cell?

Accepted Answer

It maintains electrical neutrality by allowing ion flow

Question 19

Which of the following is a correct statement about oxidation and reduction?

Accepted Answer

Oxidation is the loss of electrons

Question 20

Which of the following is the correct oxidation state for oxygen in $$CO_2$$?

Accepted Answer

-2

Electrochemistry and Redox Reactions: Study Notes for General Chemistry

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