AnswersIA-Chemistry A Survey of Chemistry AWriting and Balancing Chemical Equations

Writing and Balancing Chemical Equations — Unit test Answers

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Sodium combines with water to produce sodium hydroxide and hydrogen gas. Which word equation represents this violent reaction?

A
sodium hydroxide + water sodium + hydrogen
Option A
B
sodium + water sodium hydroxide + hydrogen
Option B
C
sodium + hydrogen sodium hydroxide + water
Option C
D
sodium + sodium hydroxide water + hydrogen
Option D
3
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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.
4

Which best describes the reducing agent in the reaction below? Cl2(aq) + 2Br–(aq) 2Cl–(aq) + Br2(aq)

Question illustration
A
Bromine (Br) loses an electron, so it is the reducing agent.
B
Bromine (Br) gains an electron, so it is the reducing agent.
C
Chlorine (Cl) loses an electron, so it is the reducing agent.
D
Chlorine (Cl) gains an electron, so it is the reducing agent.
6

Consider the reaction below. Which half reaction correctly describes the oxidation that is taking place?

Question illustration
A
Z n (s) right arrow upper Z n superscript 2 plus (a q) plus e superscript minus.
Option A
B
Upper Z n (s) right arrow upper Z n superscript 2 plus (a q) plus 2 e superscript minus.
Option B
C
Upper C u superscript 2 plus (a q) plus 2 e superscript minus right arrow upper C u (s).
Option C
D
Upper C u superscript 2 plus (a q) plus e superscript minus right arrow upper C u (s).
Option D
16

Which equation is a decomposition reaction?

A
Li2CO3 Li2O + CO2
Option A
B
Zn + HCl ZnCl2 + H2
Option B
C
Na2O + CO2 Na2CO3
Option C
D
C6H12O6 + O2 CO2 + H2O
Option D
17

What is the final, balanced equation that is formed by combining these two half reactions?

Question illustration
A
Upper C u superscript 2 plus, plus upper N upper O subscript 3 superscript minus, plus 4 e superscript minus, plus 2 upper H superscript plus right arrow upper C u plus upper N upper O subscript 2 superscript minus, plus upper H subscript 2 upper O.
Option A
B
Upper C u plus upper N upper O subscript 3 superscript minus, plus 2 upper H superscript plus right arrow upper C u superscript 2 plus, plus upper N upper O subscript 2 superscript minus, plus upper H subscript 2 upper O.
Option B
C
2 upper C u plus upper N upper O subscript 3 superscript minus plus 2 upper H superscript plus right arrow 2 upper C u superscript 2 plus, plus upper N upper O subscript 2 superscript minus, plus upper H subscript 2 upper O.
Option C
D
Upper C u plus upper N upper O subscript 3 superscript minus, plus 2 upper H superscript plus right arrow upper C u superscript 2 plus, plus upper N upper O subscript 2 superscript minus, plus 2 upper H subscript 2 upper O.
Option D
24

Consider the reaction that occurs when copper is added to nitric acid.Cu(s) + 4HNO3(aq) Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)What is the reducing agent in this reaction?

Question illustration
A
Cu
B
NO3–
C
Cu(NO3)2
D
NO2
27

Which word equation shows lithium oxide being formed from the reaction between oxygen and lithium?

A
oxygen + lithium oxide lithium
Option A
B
lithium + oxygen lithium oxide
Option B
C
oxygen + lithium lithium + oxide
Option C
D
lithium oxide lithium + oxygen
Option D
28

Which substance loses electrons in a chemical reaction?

A
the one that is oxidized, which is the oxidizing agent
B
the one that is reduced, which is the reducing agent
C
the one that is oxidized, which is the reducing agent
D
the one that is reduced, which is the oxidizing agent
30

In which two types of reactions do opposite chemical changes occur?

A
double replacement and combustion
B
single replacement and double replacement
C
synthesis and decomposition
D
combustion and synthesis
32

Chemists use activity series to determine whether which type of reaction will occur?

A
combustion
B
double replacement
C
decomposition
D
single replacement
33

Which of the following is a simple definition of reduction?

A
the loss of electrons
B
the gain of electrons
C
an agent that oxidizes something
D
an agent that reduces something
34

If a substance reacts with oxygen, the chemical reaction is most likely a

A
combustion reaction.
B
decomposition reaction.
C
single replacement reaction.
D
double replacement reaction.
35

This formula equation is unbalanced.BaCl2(aq) + Na2CO3(aq) BaCO3(s) + NaCl(aq) Which coefficient should be placed in front of NaCl to balance this equation?

Question illustration
A
1
B
2
C
3
D
4
36

Equations can be balanced by using the half-reaction method. Which step should be completed first when using this method?

A
inserting the coefficients
B
balancing the half reactions
C
identifying the half reactions
D
finding the oxidation states of atoms
37

Which word equation shows lithium oxide being formed from the reaction between oxygen and lithium?

A
oxygen + lithium oxide lithium
Option A
B
lithium + oxygen lithium oxide
Option B
C
oxygen + lithium lithium + oxide
Option C
D
lithium oxide lithium + oxygen
Option D
38

Sodium combines with water to produce sodium hydroxide and hydrogen gas. Which word equation represents this violent reaction?

A
sodium hydroxide + water sodium + hydrogen
Option A
B
sodium + water sodium hydroxide + hydrogen
Option B
C
sodium + hydrogen sodium hydroxide + water
Option C
D
sodium + sodium hydroxide water + hydrogen
Option D
39

Which best describes the reducing agent in the reaction below? Cl2(aq) + 2Br–(aq) 2Cl–(aq) + Br2(aq)

Question illustration
A
Bromine (Br) loses an electron, so it is the reducing agent.
B
Bromine (Br) gains an electron, so it is the reducing agent.
C
Chlorine (Cl) loses an electron, so it is the reducing agent.
D
Chlorine (Cl) gains an electron, so it is the reducing agent.
40

This formula equation is unbalanced.BaCl2(aq) + Na2CO3(aq) BaCO3(s) + NaCl(aq) Which coefficient should be placed in front of NaCl to balance this equation?

Question illustration
A
1
B
2
C
3
D
4
41

Which of the following is a simple definition of reduction?

A
the loss of electrons
B
the gain of electrons
C
an agent that oxidizes something
D
an agent that reduces something

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