Question 1

Which of the following best describes a redox reaction?

Accepted Answer

A reaction in which electrons are transferred between species, resulting in changes in oxidation states.

Question 2

In the reaction $$\mathrm{Zn} + \mathrm{Cu}^{2+} \rightarrow \mathrm{Zn}^{2+} + \mathrm{Cu}$$, which species is oxidized?

Accepted Answer

Zn

Question 3

What is the oxidation number of oxygen in $$\mathrm{H_2O}$$?

Accepted Answer

$$-2$$

Question 4

Which statement about oxidation numbers is correct?

Accepted Answer

The oxidation number of fluorine in compounds is always $$-1.$$

Question 5

Given the reaction $$2\mathrm{$$FeCl_2$$} + \mathrm{Cl_2$} \rightarrow 2\mathrm{$$FeCl_3$$}$$, what is the change in oxidation state for iron?

Accepted Answer

From $$+2 to$$ $$+3$$

Question 6

In a galvanic cell, where does oxidation occur?

Accepted Answer

At the anode

Question 7

Which of the following is the correct half-reaction for the reduction of copper(II) ions?

Accepted Answer

$$\mathrm{Cu}^{2+} + 2e^- \rightarrow \mathrm{Cu}$$

Question 8

What is the oxidation number of sulfur in $$\mathrm{SO_4$^{2-}}$$?

Accepted Answer

$$+6$$

Question 9

Which of the following best explains why a salt bridge is necessary in a galvanic cell?

Accepted Answer

It maintains electrical neutrality by allowing ion migration.

Question 10

In the reaction $$\mathrm{Fe_2O_3} + 3\mathrm{C} \rightarrow 2\mathrm{Fe} + 3\mathrm{CO}$$, which species acts as the reducing agent?

Accepted Answer

C

Question 11

Which of the following is true about the oxidation number of hydrogen?

Accepted Answer

It is $$+1$$ when bonded to nonmetals and $$-1$$ when bonded to metals.

Question 12

A student mixes $$\mathrm{Zn}$$ metal with $$\mathrm{$$CuSO_4$$}$$ solution. What is the net ionic equation for the redox reaction that occurs?

Accepted Answer

$$\mathrm{Zn} + \mathrm{Cu}^{2+} \rightarrow \mathrm{Zn}^{2+} + \mathrm{Cu}$$

Question 13

Which of the following is NOT a correct rule for assigning oxidation numbers?

Accepted Answer

The oxidation number of oxygen in peroxides is $$-2.$$

Question 14

In the reaction $$\mathrm{2H_2O_2} \rightarrow 2\mathrm{H_2O} + \mathrm{O_2$}$$, what is the change in oxidation state for oxygen?

Accepted Answer

From $$-1 to$$ $$-2$$ and $$0$$

Question 15

Which of the following compounds contains an element with an oxidation number of $$+5$$?

Accepted Answer

$$\mathrm{$$HNO_3$$}$$

Question 16

A redox reaction occurs in a battery powering a flashlight. Which process happens at the cathode?

Accepted Answer

Reduction

Question 17

Which of the following best describes the role of the oxidizing agent in a redox reaction?

Accepted Answer

It gains electrons and is reduced.

Question 18

In the reaction $$\mathrm{2Na} + \mathrm{Cl_2$} \rightarrow 2\mathrm{NaCl}$$, what is the oxidation number of sodium in the product?

Accepted Answer

$$+1$$

Question 19

Which of the following is a correct definition of oxidation in terms of electron transfer?

Accepted Answer

Oxidation is the loss of electrons by a species.

Redox Reactions: Concepts, Oxidation Numbers, and Applications

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