AnswersMO-Physical Science A-CRUnit Test

Unit Test — Unit test Answers

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Harvey mixes two liquids. Which observation of the new mixture most likely indicates a precipitate is forming?

A
a cloudy appearance
B
a bubble formation
C
a change in color
D
a change in odor
2
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What does the octet rule state that explains why atoms bond?

A
An atom bonds to have eight valence electrons to become stable.
B
An atom bonds to lose eight valence electrons to become stable.
C
An atom bonds to have eight valence electrons to become unstable.
D
An atom bonds to lose eight valence electrons to become unstable.
3

Lexi is balancing equations. She is finding one equation to be very difficult to balance. Which explains how to balance the equation ZnSO4 + Li2CO3 → ZnCO3 + Li2SO4?

A
One reactant and one product needs the coefficient 2.
B
The products both need a 3 coefficient.
C
The reactants both need a 2 coefficient.
D
Atoms in the equation are already in balance.
4

Consider the equation below.What is the equilibrium constant expression for the given reaction?

Question illustration
A
K subscript e q equals StartFraction bracket upper C a upper O EndBracket over upper C a upper C upper O subscript 3 EndBracket EndFraction.
Option A
B
K subscript e q equals StartFraction StartBracket upper C upper O subscript 2 EndBracket StartBracket upper C a upper O EndBracket over StartBracket upper C a upper C upper O subscript 3 EndBracket EndFraction.
Option B
C
K subscript e q equals StartBracket upper C upper O subscript 2 EndBracket.
Option C
D
K subscript e q equals StartFraction 1 over StartBracket upper C upper O subscript 2 EndBracket EndFraction.
Option D
5

Hydrochloric acid and sodium hydroxide can be combined to form sodium chloride and water. Which best explains the reaction?

A
The mass of sodium hydroxide will result in the same mass of sodium chloride.
B
The total mass of hydrochloric acid and sodium hydroxide will result in a lower total mass of sodium chloride and water.
C
The mass of hydrochloric acid will result in the same mass of sodium chloride.
D
The total mass of hydrochloric acid and sodium hydroxide will result in the same total mass of sodium chloride and water.
6

Which clue can be used to identify a chemical reaction as a decomposition reaction?

A
The reaction involves oxygen.
B
The reaction involves ions.
C
The reaction has a single reactant.
D
The reaction has a single product.
7

Which refers to the type of chemical bond that involves the transfer of electrons between atoms?

A
metallic
B
polar covalent
C
ionic
D
covalent
8

Which type of reaction has the general formula of AB + CD → AD + CB?

A
synthesis
B
decomposition
C
oxidation
D
replacement
9

Chemical A and Chemical B react in an exothermic reaction. What can be known about what will happen when Chemical A and Chemical B are mixed together?

A
The old substance will need more energy to break its chemical bonds than the new substance will release.
B
More energy will be released from the old substance than the new substance will release to form its chemical bonds.
C
The color will change as a result of the reaction.
D
The substance will bubble as a result of the reaction.
10

Which statement best describes the diagram below?

Question illustration
A
The pressure is greater at the bottom of the container.
B
The pressure is greater at the top of the container.
C
The temperature is greater at the top of the container.
D
The temperature is greater at the bottom of the container.
11

Which symbol in a chemical equation separates the reactants from the products?

A
=
B
→
C
>
D
+
12

In which reaction would the activation energy result in an endothermic reaction?

A
water freezing
B
an egg cooking
C
a candle burning
D
iron rusting
13

Thirty grams of lead oxide and fifteen grams of ammonia react completely to produce solid lead, nitrogen gas, and liquid water. What will be approximate mass of all three products?

A
10 g
B
15 g
C
45 g
D
450 g
14

Consider the chemical equilibrium of a soap that is present in its aqueous solution. C17H35COONa(aq) C17H35COO–(aq) + Na+(aq)sodium stearate (soap) stearate ion What will happen if a large quantity of NaCl is added to the aqueous solution?

Question illustration
A
The equilibrium will shift to the right, favoring the dissociation of soap in aqueous solution.
B
The equilibrium will shift to the left to such an extent that it leads to the precipitation of solid soap.
C
The equilibrium will not be affected by the addition of NaCl to the solution.
D
The equilibrium will be permanently destroyed by the addition of NaCl.
15

Which will not appear in the equilibrium constant expression for the reaction below?

Question illustration
A
[H2O]
B
[C]
C
[H2]
D
[CO]
16

Consider the following equation in chemical equilibrium. C2H4(g) + H2(g) C2H6(g) + 137 kJ What happens to the amount of ethane (C2H6) when the temperature of the system is increased?

Question illustration
A
The amount of ethane decreases.
B
The amount of ethane increases initially and then decreases.
C
The amount of ethane increases.
D
The amount of ethane decreases initially and then increases.
17

What are the products of the combustion of a hydrocarbon?

A
carbon and oxygen
B
carbon dioxide and water
C
carbon and hydrogen
D
carbon dioxide and hydrogen
18

Which balances the equation Mg + O2 → MgO?

A
Mg + 2O2 → 4MgO
B
2Mg + 2O2 → 2MgO
C
2Mg + O2 → 2MgO
D
2Mg + 2O2 → 4MgO
19

The release of a gas from a chemical reaction is very quick. A scientist wants to measure what is released, but in small increments. What would allow the scientist to change the rate of the reaction so the results could be measured?

A
an enzyme
B
an inhibitor
C
a depressant
D
an accelerator
20

The Statue of Liberty is made out of copper and was once shiny and copper-colored. Over the years, the copper has gone through a process called oxidation, where it has changed into a new material.

A
an endothermic reaction
B
an energy formation
C
a chemical reaction
D
a precipitate formation

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