AnswersTX-Chemistry B-Credit Recovery Summer SchoolCumulative Exam

Cumulative Exam — Cumulative exam Answers

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An experimental procedure requires 10 ml of acid to be dissolved into a beaker of water. An additional 5 ml of acid is added to the solution. Which statement best describes the new solution?

A
the strength of the acid in the solution has been increased
B
the concentration of acid in the solution has decreased by one half
C
the concentration of acid in the solution has been increased
D
the strength of the acid in the solution has decreased by one half
2
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Why does the presence of lone pair electrons contribute to the polarity of a water molecule?

A
They allow the bonds between oxygen and hydrogen to be single.
B
They increase the partial positive charge on the oxygen atom.
C
They prevent the atoms from forming a linear molecule.
D
They counter the uneven pull on electrons between the atoms.
3

A miner develops cancer of the esophagus. Ten years before, he had been exposed to radiation when he worked for a year in a mine. He had also smoked cigarettes for a number of years, but had quit five years ago. Which statement best describes the miner’s condition?

A
Tests can determine whether the cancer was caused by exposure at the mine or by compounds in cigarette smoke so that a treatment can be determined.
B
Cancer caused by exposure at the mine would have appeared while he was at the mine, so smoking is the more likely cause.
C
The cancer is likely the result of natural exposure to radiation in the environment and not related to either the mine or smoking.
D
It is unlikely that a specific cause can be determined, but the treatment would likely be the same in either case.
4

The pOH of a solution is 6.0. Which statement is correct?Use and .

Question illustration
A
The pH of the solution is 20.0.
B
The concentration of OH– ions is .
Option B
C
The concentration of OH– ions is .
Option C
D
The pH of the solution is 8.0.
5

A gas in a rigid container at 25°C has a pressure of 0.96 atm. A change in temperature causes the pressure to increase to 1.25 atm. What is the new temperature of the gas?Use .

Question illustration
A
–44.2°C
B
32.6°C
C
115°C
D
388°C
6

Pure water at 25°C

A
ionizes in the presence of acid to form an equilibrium in which
Option A
B
ionizes in the presence of acid to form an equilibrium in which
Option B
C
self-ionizes to form an equilibrium in which
Option C
D
self-ionizes to form an equilibrium in which
Option D
7

What is a common use of bases?

A
as a component of vinegar
B
as a component of car batteries
C
to make foods tart
D
to reduce indigestion
8

Which represents the ionization of a strong electrolyte?

A
CH3OH(l) CH3OH(aq)
Option A
B
K3PO4(s) 3K+(aq) + PO43–(aq)
Option B
C
H2CO3(aq) H+(aq) + HCO3–(aq)
Option C
D
CH3COOH(aq) + H2O(l) H3O+(aq) + CH3COO–(aq)
Option D
9

A supervisor spends a day inspecting a nuclear plant for potential radiation leaks. She has to move throughout the plant inspecting all the equipment and machinery. She needs to take two different radiation detection devices to help ensure her safety and to find radiation leaks. She needs the results immediately. Which two devices would be the best choices for the task?

A
Geiger counter and scintillation counter
B
Geiger counter and cloud chamber
C
cloud chamber and scintillation counter
D
film badge and scintillation counter
10

Which is an example of ionization?

A
C + O2 CO2
Option A
B
H2CO3 H2O + CO2
Option B
C
SO2 + H2O HSO3– + H+
Option C
D
Mg(OH)2 Mg2+ + 2OH–
Option D
11

Which value is most likely to be the pH of a salt solution that is formed by the reaction of a strong acid and a weak base?

A
2.0
B
7.0
C
8.0
D
10.0
12

Which contributes to the dissolution of sugar in water?

A
the dissociation of an ionic compound in water
B
a strong pull of water molecules on an ionic compound
C
the dissociation of a polar covalent compound in water
D
a strong pull of water molecules on a polar covalent compound
13

Ethyne (C2 H2 (g), Hf = 226.77 kJ/mol) undergoes complete combustion in the presence of oxygen to produce carbon dioxide (CO2 (g), Hf = –393.5 kJ/mol ) and water (H2 O(g), Hf = –241.82 kJ/mol) according to the equation below.What is the enthalpy of combustion (per mole) of C2 H2 (g)? Use .

Question illustration
A
–2511.2 kJ/mol
B
–1255.6 kJ/mol
C
–862.1 kJ/mol
D
–431.0 kJ/mol
14

Which of the following shows a Bronsted-Lowry acid reacting?

A
CO + NO2 CO2 + NO
Option A
B
NH3 + H+ NH4+
Option B
C
+ H+ HCO3–
Option C
D
HCl + H2O H3O+ + Cl–
Option D
15

In the disproportionation reaction CI2 + H2OHCIO + HCI, what describes the oxidation states of the substance Cl?

Question illustration
A
Cl has an oxidation number of 2 in Cl2. It is then reduced to Cl with an oxidation number of 1 in both HCl and HClO.
B
Cl has an oxidation number of –1 in Cl2. It is then oxidized to Cl with an oxidation number of 1 in both HCl and HClO.
C
Cl has an oxidation number of 0 in Cl2. It is then reduced to CI- with an oxidation number of –1 in both HCl and HClO.
D
Cl has an oxidation number of 0 in Cl2. It is then reduced to CI- with an oxidation number of –1 in HCl and is oxidized to Cl+ with an oxidation number +1 in HClO.
16

How does heat differ from temperature?

A
Temperature is the measure of heat.
B
Temperature and heat are the same thing.
C
Temperature measures thermal energy, and heat is the flow of thermal energy.
D
Temperature measures the loss of energy, and heat measures the gain of energy.
17

Ca(OH)2 is added to a large beaker of water. How is the solution different from the original water?

A
The solution turns blue litmus to red.
B
The solution turns phenolphthalein pink.
C
The solution has more hydrogen ions.
D
The solution has fewer hydroxide ions.
18

The enthalpy of formation of water is –285.8 kJ/mol. What can be inferred from this statement?

A
The enthalpy of the products is equal to the enthalpy of the reactants.
B
Heat is absorbed during the process.
C
Heat is released during the process.
D
The enthalpy of the products is more than the enthalpy of the reactants.
19

Consider the diagram.Which postulate of the kinetic-molecular theory best describes the event in the diagram?

Question illustration
A
Most of the volume of a gas is empty space.
B
All collisions between particles are perfectly elastic.
C
There is no force of attraction or repulsion between gas particles.
D
The average kinetic energy of particles depends only on temperature.
20

Which statement best explains why different gases effuse at different rates?

A
At a given pressure, gas particles with smaller masses move faster.
B
At a given pressure, gas particles with smaller masses move slower.
C
At a given temperature, gas particles with smaller masses move faster.
D
At a given temperature, gas particles with smaller masses move slower.

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