AnswersCR03101 ChemistryUnit Test

Unit Test — Unit test Answers

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What is the word equation for atoms of magnesium reacting with molecules of oxygen to produce magnesium oxide?

A
magnesium + magnesium oxide oxygen
Option A
B
magnesium + oxygen magnesium oxide
Option B
C
magnesium oxide + oxygen magnesium
Option C
D
magnesium + oxygen magnesium + oxygen
Option D
2
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Which statement describes a chemical reaction?

A
Reactants form products when atoms change state.
B
Products form reactants when atoms change state.
C
Reactants form products when atoms are rearranged.
D
Products form reactants when atoms are rearranged.
3

Which of these scenarios is most likely a chemical reaction?

A
A gas turns into a liquid as it releases energy.
B
A liquid becomes a gas as it absorbs energy.
C
Two white solids are added to a colorless liquid, and a colorless liquid remains.
D
Two colorless liquids are added together, and a colorless liquid and a green solid remain.
4

Which reaction will most likely take place based on the activity series?Li > K > Ba > Ca > Na > Mn > Zn > Cr > Fe > Cd > Ni > H > Sb > Cu > Ag > Pd > Hg > Pt

A
Pt + FeCl3
Option A
B
Mn + CaO
Option B
C
Li + ZnCO3
Option C
D
Cu + 2KNO3
Option D
5

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

Question illustration
A
Chlorine is losing electrons and being oxidized.
B
Chlorine is losing electrons and being reduced.
C
Chlorine is gaining electrons and being oxidized.
D
Chlorine is gaining electrons and being reduced.
6

The equation shows lead reacting with sulfuric acid to produce lead sulfate and hydrogen gas.Which type of chemical reaction does this equation represent?

Question illustration
A
synthesis
B
decomposition
C
single replacement
D
double replacement
7

Which statement best applies collision theory to preventing a dangerous reaction from occurring?

A
Store the reactants together at a low pressure.
B
Keep all sparks or flames away from the reactants.
C
Store the reactants together at a low temperature.
D
Keep the reactants in separate containers.
8

Which energy graph represents the nonspontaneous transition of graphite into diamond?

A
A graph with Reaction progression on the horizontal axis and energy on the vertical axis. A line starts low on the vertical axis, runs briefly parallel to the horizontal axis, slopes up sharply, curves down a short distance, and levels out.
Option A
B
A graph with Reaction progression on the horizontal axis and energy on the vertical axis. A line starts midway up the vertical axis, runs briefly parallel to the horizontal axis, slopes up sharply, curves down sharply, and levels out below the initial starting point.
Option B
C
A graph with Reaction progression on the horizontal axis and energy on the vertical axis. A line starts midway up the vertical axis, runs briefly parallel to the horizontal axis, slopes up a small amount, then curves down to level out below the initial starting point.
Option C
D
A graph with Reaction progression on the horizontal axis and energy on the vertical axis. A line starts midway up the vertical axis, runs briefly parallel to the horizontal axis, slopes up a moderate amount, then curves down sharply to level out below the initial starting point.
Option D
9

Which statement defines enzymatic activity?

A
Enzymes are required to slow down biological reactions within cells.
B
Specific enzymes can catalyze a wide variety of chemical reactions.
C
Enzymes regulate cellular functions through feedback mechanisms.
D
Enzymes bind substrates so that reactive groups have many different orientations.
10

Combustion of gasoline in automobiles produces poisonous gases. Catalytic converters that contain solid platinum, palladium, and rhodium change these poisonous gases into harmless gases. Which statement describes the catalyst?

A
It is a homogeneous catalyst.
B
It provides an alternative pathway for the reaction.
C
It combines with poisonous gases to make them harmless.
D
It increases the energy that is needed for the reaction to occur.
11

Which of the following is not an oxidation-reduction reaction?

A
XeF6(s) XeF4(s) + F2(g)
Option A
B
2Cs(s) + I2(g) 2CsI(s)
Option B
C
2H2SO4(aq) + 2Ba(OH)2(aq) 2BaSO4(s) + 4H2O(l)
Option C
D
Zn(s) + 2AgNO3(aq) Zn(NO3)2(aq) + Ag(s)
Option D
12

Consider the half reactions below for a chemical reaction.What is the overall equation for this chemical reaction?

Question illustration
A
Upper Z n (s) plus upper C u superscript 2 plus (a q) right arrow upper Z n superscript 2 plus (a q) plus upper C u (s).
Option A
B
Upper Z n (s) plus upper C u superscript 2 plus (a q) right arrow upper C u superscript 2 plus (a q) plus upper Z n (s).
Option B
C
Upper Z n superscript 2 plus (a q) plus upper C u (s) right arrow upper C u superscript 2 plus (a q) plus upper Z n (s).
Option C
D
Upper Z n superscript 2 plus (a q) plus 2 e superscript minus right arrow upper C u superscript 2 plus (a q) plus 2 e superscript plus.
Option D
13

What is the word equation for atoms of magnesium reacting with molecules of oxygen to produce magnesium oxide?

A
magnesium + magnesium oxide oxygen
Option A
B
magnesium + oxygen magnesium oxide
Option B
C
magnesium oxide + oxygen magnesium
Option C
D
magnesium + oxygen magnesium + oxygen
Option D
14

Consider the chemical equation for the combustion of sugar._C6H12O6(s) + _O2(g) _CO2(g) + _H2O(l)Which sequence of coefficients should be placed in the blanks to balance this equation?

Question illustration
A
1, 6, 6, 6
B
6, 1, 6, 1
C
3, 3, 3, 6
D
1, 3, 3, 6
15

This formula equation is unbalanced.Pb(NO3)2(aq) + Li2SO4(aq) PbSO4(s) + LiNO3(aq) Which coefficient should appear in front of LiNO3 in the balanced equation?

Question illustration
A
1
B
2
C
3
D
4
16

Consider the reaction.When does the given chemical system reach dynamic equilibrium?

Question illustration
A
when the forward and reverse reactions stop
B
when the rate of the forward reaction is higher than the rate of the reverse reaction
C
when the concentration of the reactants is higher than the concentration of the products
D
when the rates of the forward and reverse reactions are equal
17

Which rule for assigning oxidation numbers is correct?

A
Hydrogen is usually –1.
B
Oxygen is usually –2.
C
A pure group 1 element is +1.
D
A monatomic ion is 0.
18

What is the oxidation number for N in the compound NH3? (Recall that H usually has an oxidation number of +1.)

A
–3
B
–1
C
0
D
+3
19

Consider the reaction below.What is being reduced?

Question illustration
A
only K
B
only Br2
C
both K and Br2
D
neither K nor Br2
20

The reaction below was carried out in an acidic solution.Which statement is true about this equation?

Question illustration
A
Although it is unbalanced, it can be balanced by using the half-reaction method.
B
It has been balanced by using the half-reaction method.
C
It has been balanced by directly using spectator ions.
D
Although it is unbalanced, it can be balanced by directly using spectator ions.

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