Question 1

What is the total number of atoms in calcium phosphate, Ca3(PO4)2?

Accepted Answer

A) 8 
B) 9 
C) 11 
D) 13 
A) 8 
B) 9 
C) 11 
D) 13 D

Question 2

The empirical formula gives the actual number of atoms of each kind in a compound.

Accepted Answer

A) True 
 B)False  False

Question 3

In a chemical equation, the reactants are found on the left side of the arrow.

Accepted Answer

A) True 
 B)False  True

Question 4

When compounds containing carbon and hydrogen are burned in air, the products are usually carbon dioxide and water.

Accepted Answer

A) True 
 B)False

Question 5

Chemists effectively count atoms by weighing matter.

Accepted Answer

A) True 
 B)False

Question 6

A decomposition reaction always breaks down a compound into the elements that make up the compound.

Accepted Answer

A) True 
 B)False

Question 7

An oxidizing agent is a substance that

Accepted Answer

A) reacts with oxygen. 
B) removes electrons from another substance. 
C) supplies electrons to another substance. 
D) frees a metal from its ore. 
A) reacts with oxygen. 
B) removes electrons from another substance. 
C) supplies electrons to another substance. 
D) frees a metal from its ore.

Question 8

The reaction: potassium chlorate  
 potassium chloride and oxygen gas is an example of

Accepted Answer

A) decomposition. 
B) combination. 
C) replacement. 
D) ion exchange. 
A) decomposition. 
B) combination. 
C) replacement. 
D) ion exchange.

Question 9

What is the empirical formula of C4H8?

Accepted Answer

A) CH 
B) CH2 
C) C4H8 
D) C2H4 
A) CH 
B) CH2 
C) C4H8 
D) C2H4

Question 10

When balancing a chemical equation, you need to change subscripts to make the number of atoms of an element the same on both sides of the equation.

Accepted Answer

A) True 
 B)False

Question 11

What is the mass of 0.50 mole of baking soda, NaHCO3?

Accepted Answer

A) 26 g 
B) 42 g 
C) 84 g 
D) 168 g 
A) 26 g 
B) 42 g 
C) 84 g 
D) 168 g

Question 12

What is the formula weight of methane, CH4?

Accepted Answer

A) 13 u 
B) 16 u 
C) 52 u 
D) None of the above. 
A) 13 u 
B) 16 u 
C) 52 u 
D) None of the above.

Question 13

What is the number of oxygen atoms in Al2(SO4)3?

Accepted Answer

A) 3 
B) 4 
C) 7 
D) 12 
A) 3 
B) 4 
C) 7 
D) 12

Question 14

A chemical reaction is balanced by changing (the)

Accepted Answer

A) subscripts. 
B) superscripts. 
C) coefficients. 
D) Any of the above as needed. 
A) subscripts. 
B) superscripts. 
C) coefficients. 
D) Any of the above as needed.

Question 15

Because of our belief in the law of conservation of mass, it seems reasonable that

Accepted Answer

A) in combustion reactions, part of the mass of the reactants must be converted into fire. 
B) the mass of a newly formed compound cannot be changed. 
C) molecules cannot be broken down, for the mass would be reduced. 
D) the number of atoms of reactants must equal the number of atoms of products. 
A) in combustion reactions, part of the mass of the reactants must be converted into fire. 
B) the mass of a newly formed compound cannot be changed. 
C) molecules cannot be broken down, for the mass would be reduced. 
D) the number of atoms of reactants must equal the number of atoms of products.

Question 16

The reaction 2 Mg + O2 $\rarr$ 2 MgO is an example of

Accepted Answer

A) oxidation. 
B) combination. 
C) combustion. 
D) All of the above. 
A) oxidation. 
B) combination. 
C) combustion. 
D) All of the above.

Question 17

What is the total mass of products in the methane reaction shown before question 11?

Accepted Answer

A) 80 u 
B) 64 u 
C) 62 u 
D) 48 u 
A) 80 u 
B) 64 u 
C) 62 u 
D) 48 u

Question 18

In combination reactions, elements react to form compounds.

Accepted Answer

A) True 
 B)False

Question 19

The reaction: 2 NaI + Cl2 $\rarr$ 2 NaCl + I2 is an example of

Accepted Answer

A) decomposition. 
B) combination. 
C) replacement. 
D) ion exchange. 
A) decomposition. 
B) combination. 
C) replacement. 
D) ion exchange.

Question 20

Substances that lose electrons in reactions are called oxidizing agents.

Accepted Answer

A) True 
 B)False

Exam 10: Chemical Reactions

What is the total number of atoms in calcium phosphate, Ca3(PO4)2?

The empirical formula gives the actual number of atoms of each kind in a compound.

In a chemical equation, the reactants are found on the left side of the arrow.

When compounds containing carbon and hydrogen are burned in air, the products are usually carbon dioxide and water.

Chemists effectively count atoms by weighing matter.

A decomposition reaction always breaks down a compound into the elements that make up the compound.

An oxidizing agent is a substance that

The reaction: potassium chlorate potassium chloride and oxygen gas is an example of

What is the empirical formula of C4H8?

When balancing a chemical equation, you need to change subscripts to make the number of atoms of an element the same on both sides of the equation.

What is the mass of 0.50 mole of baking soda, NaHCO3?

What is the formula weight of methane, CH4?

What is the number of oxygen atoms in Al2(SO4)3?

A chemical reaction is balanced by changing (the)

Because of our belief in the law of conservation of mass, it seems reasonable that

The reaction 2 Mg + O2 →\rarr→ 2 MgO is an example of

What is the total mass of products in the methane reaction shown before question 11?

In combination reactions, elements react to form compounds.

The reaction: 2 NaI + Cl2 →\rarr→ 2 NaCl + I2 is an example of

Substances that lose electrons in reactions are called oxidizing agents.

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What is the total number of atoms in calcium phosphate, Ca₃(PO₄)₂?

What is the empirical formula of C₄H₈?

What is the mass of 0.50 mole of baking soda, N_aHCO₃?

What is the formula weight of methane, CH₄?

What is the number of oxygen atoms in Al₂(SO₄)₃?

The reaction 2 M_g + O₂ $\rarr$ 2 M_gO is an example of

The reaction: 2 NaI + Cl₂ $\rarr$ 2 NaCl + I₂ is an example of