AnswersTX-Chemistry BUnit Test

Unit Test — Cumulative exam Answers

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Consider the half reaction below.Which statement best describes what is taking place in this half reaction?

Question illustration
A
Iron is being reduced.
B
Iron is being oxidized.
C
Iron is gaining electrons.
D
Iron is an oxidizing agent.
2
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An ice cube is dropped into a glass of milk at 20°C. Which statement explains the transfer of kinetic energy (KE)?

A
Because milk has higher KE than ice, KE is transferred from the milk to the molecules of ice.
B
Because milk has higher KE than ice, KE is transferred from the molecules of ice to the milk.
C
Because ice has higher KE than milk, KE is transferred from the milk to the molecules of ice.
D
Because ice has higher KE than milk, KE is transferred from the molecules of ice to the milk.
3

Which substance has Hf defined as 0 kJ/mol?

Question illustration
A
H2O (s)
B
Ne (l)
C
F2 (g)
D
CO2 (g)
4

The following equations are half reactions and reduction potentials. Ag+(aq) + e– Ag(s) has a reduction potential of +0.80 V. Cr3+(aq) + 3e– Cr(s) has a reduction potential of –0.74 V.Which statement best compares the substances in these half reactions?

Question illustration
A
A silver ion gains electrons more easily and is a stronger oxidizing agent than a chromium(III) ion.
B
A silver ion loses electrons more easily and is a stronger oxidizing agent than a chromium(III) ion.
C
A silver ion gains electrons more easily and is a stronger reducing agent than a chromium(III) ion.
D
A silver ion loses electrons more easily and is a stronger reducing agent than a chromium(III) ion.
5

The table shows the characteristics of four substances after they are placed in water.Substance Ion concentrationElectrical conductivity WMediumGoodXLowPoorYHighExcellentZNoneNoneWhich compound is most likely the strongest electrolyte?

A
W
B
X
C
Y
D
Z
6

Which term refers to the formation of ions as a result of a chemical reaction?

A
dissociation
B
electrolyte
C
hydration
D
ionization
7

A scientist is examining a mixture of nitrogen, hydrogen, and ammonia. The individual pressures that are exerted by nitrogen and hydrogen are 0.26 atm and 0.28 atm, respectively. If the total pressure is 0.90 atm, what is the partial pressure of ammonia?Use .

Question illustration
A
0.27 atm
B
0.36 atm
C
0.54 atm
D
0.90 atm
8

Consider the three equations below.Which statement do these reactions best support?

Question illustration
A
Beta decay occurs only in certain atoms.
B
Alpha decay occurs only in certain atoms.
C
Chain reactions play important roles in the process of nuclear fission.
D
Nuclear fusion plays an important role in making elements that are heavier than helium.
9

The pH of lemon juice at 298 K is found to be 2.32. What is the concentration of ions in the solution? Use .

Question illustration
A
1.05 times 10 to the negative 3 moles per liter.
Option A
B
4.79 times 10 to the negative 3 moles per liter.
Option B
C
2.09 times 10 squared moles per liter.
Option C
D
9.55 times 10 squared moles per liter.
Option D
10

Which quantity is held constant when working with Boyle’s, Charles’s, and Gay-Lussac’s laws?

A
volume
B
moles
C
pressure
D
temperature
11

Consider the chemical equation below.Which is the net ionic equation?

Question illustration
A
Upper H superscript plus, plus upper O upper H superscript minus right arrow upper H subscript 2 upper O.
Option A
B
Upper M g superscript 2 plus, plus 2 upper O upper H superscript minus, plus 2 upper H superscript plus right arrow upper M g superscript 2 plus, plus 2 upper H subscript 2 upper O.
Option B
C
Upper M g superscript 2 plus, plus 2 upper N upper O subscript 3 superscript minus right arrow upper M g superscript 2 plus plus 2 upper N upper O subscript 3 superscript minus.
Option C
D
Upper M g superscript 2 plus plus 2 upper O upper H superscript minus plus 2 upper H superscript plus plus 2 upper N upper O subscript 3 superscript minus right arrow upper M g superscript 2 plus, plus 2 upper N upper O subscript 3 superscript minus plus 2 upper H subscript 2 upper o.
Option D
12

Four different solutions (I, II, III, and IV) are labeled on the pH scale below.Why would solution IV be considered the most concentrated base out of the four substances?

Question illustration
A
It has the highest concentration of hydrogen ions.
B
It has the highest concentration of hydronium ions.
C
It has the highest concentration of oxide ions.
D
It has the highest concentration of hydroxide ions.
13

Which best describes what forms in nuclear fission?

A
two smaller, more stable nuclei
B
two larger, less stable nuclei
C
one smaller, less stable nucleus
D
one larger, more stable nucleus
14

Which defines the average kinetic energy of a system’s particles?

A
density
B
pressure
C
temperature
D
volume
15

What is the relationship between Ka and Kb with Kw?

A
The sum of Ka and Kb equals the auto-dissociation constant for water.
B
The product of Ka and Kb equals the auto-dissociation constant for water.
C
The quotient of Ka and Kb equals the auto-dissociation constant for water.
D
The difference of Ka and Kb equals the auto-dissociation constant for water.
16

Which statement best describes the process of making a solution by diluting a stock solution?

A
Add more solute to decrease the concentration.
B
Add more solute to increase the concentration.
C
Add more solvent to decrease the concentration.
D
Add more solvent to increase the concentration.
17

Which statement best explains the change that occurs when gas particles move more slowly?

A
The temperature increases because the average kinetic energy decreases.
B
The temperature increases because the average kinetic energy increases.
C
The temperature decreases because the average kinetic energy decreases.
D
The temperature decreases because the average kinetic energy increases.
18

A radioactive nuclide that is used for radiation therapy for cancer has 33 neutrons and a mass number of 60. Which is the correct symbol for this nuclide?

A
Superscript 27 subscript 60 upper C o.
Option A
B
Superscript 33 subscript 60 upper C o.
Option B
C
Superscript 60 subscript 33 upper C o.
Option C
D
Superscript 60 subscript 27 upper C o.
Option D
19

Which represents a double replacement reaction and would occur?

A
NH4NO3(aq) + AgCIO3(aq) AgNO3(aq) + NH4CIO3(aq)
Option A
B
Na2CO3(aq) + CaCl2(aq) 2NaCl(aq) + CaCO3(s)
Option B
C
NaF(aq) + KCl(aq) NaCl(aq) + KCl(aq)
Option C
D
NaCl(aq) Na+(aq) + Cl-(aq)
Option D
20

An acid has an acid dissociation constant of 2.8 10–9. What is the base dissociation constant of its conjugate base? Use .

Question illustration
A
2.8 10–23
Option A
B
3.6 10–6
Option B
C
2.8 105
Option C
D
3.6 1022
Option D

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