Deck 6: Chemical Reactions: an Introduction

Question 1

You are asked to balance the chemical equation H₂ + O₂ $\rightarrow$ H₂O. How many of the following ways are correct ways to balance this equation? I. 2H₂ + O₂ $\rightarrow$ 2H₂O
II) H₂ + O₂ $\rightarrow$ H₂O
III) 4H₂ + 2O₂ $\rightarrow$ 4H₂O
IV) H₂ + O₂ $\rightarrow$ H₂O₂

A) 0
B) 1
C) 2
D) 3
E) 4

Answer 1

3

Question 2

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? PCl₅ + H₂O $\rightarrow$ H₃PO₄ + HCl

A) 1
B) 2
C) 3
D) 4
E) 5

Answer 2

5

Question 3

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? Al + Fe₃O₄ $\rightarrow$ Al₂O₃ + Fe

A) 1
B) 3
C) 6
D) 9
E) 12

Answer 3

9

Question 4

All of the following are clues that a chemical reaction has taken place except

A) A color change occurs.
B) A solid forms.
C) The reactant is smaller.
D) Bubbles form.
E) A flame occurs.

Question 5

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? NO₂ + H₂O $\rightarrow$ HNO₃ + NO

A) 1
B) 2
C) 3
D) 4
E) 5

Question 6

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? CH₃OH + O₂ $\rightarrow$ CO₂ + H₂O

A) 1
B) 2
C) 3
D) 4
E) 6

Question 7

The equation N₂ + 3H₂ $\rightarrow$ 2NH₃ means that 1 g of N₂ reacts with 3 g of H₂ to form 2 g of NH₃.

Question 8

Consider the reaction represented by the unbalanced equation NH₃ + O₂ $\rightarrow$ NO + H₂O. For every 3.61 mol of NH₃ that reacts, _______ mol of O₂ is required.

A) 4.51
B) 3.61
C) 14.44
D) 2.89
E) none of these

Question 9

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? Pb(NO₃)₂ + K₂CO₃ $\rightarrow$ PbCO₃ + KNO₃

A) 5
B) 4
C) 3
D) 2
E) 1

Question 10

Sodium metal reacts with water to produce aqueous sodium hydroxide and hydrogen gas. Write the balanced equation for this reaction.

Question 11

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? Na₂S₂O₃ + I₂ $\rightarrow$ NaI + Na₂S₄O₆

A) 1
B) 2
C) 3
D) 4
E) 6

Question 12

Coefficients can be fractions when we are balancing a chemical equation.

Question 13

Balance the following equation in standard form and determine the sum of the coefficients.

A) 3
B) 4
C) 6
D) 7
E) 14

Question 14

Consider a reaction given by the equation aA + bB $\rightarrow$ cC + dD. In this equation A, B, C, D represent chemicals, and a, b, c, d represent coefficients in the balanced equation. For a given reaction, how many values are there for the quantity "c/d"?

A) 1
B) 2
C) 3
D) 4
E) an infinite number

Question 15

Balance the following equation in standard form and determine the sum of the coefficients. LiAlH₄(s) + AlCl₃(s) $\rightarrow$ AlH₃(s) + LiCl(s)

A) 8
B) 9
C) 10
D) 11
E) 12

Question 16

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? P₄O₁₀ + H₂O $\rightarrow$ H₃PO₄

A) 10
B) 6
C) 4
D) 2
E) 1

Question 17

Which of the following statements is not true of balancing a chemical equation?

A) Subscripts in the reactants must be conserved in the products.
B) Coefficients are used to balance the atoms on both sides.
C) The law of conservation of matter must be followed.
D) Phases are often shown for each compound but are not critical to balancing an equation.
E) All of the above statements (a-d) are true.

Question 18

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? Sn + NaOH $\rightarrow$ Na₂SnO₂ + H₂

A) 1
B) 2
C) 3
D) 4
E) 5

Question 19

Aluminum oxide solid reacts with gaseous carbon monoxide to produce aluminum metal and carbon dioxide gas. Write the balanced equation for this reaction.

Question 20

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? MnO₂ + HCl $\rightarrow$ MnCl₂ + Cl₂ + H₂O

A) 5
B) 4
C) 3
D) 2
E) 1

Question 21

Balance the equation
MgCl₂ + K₃PO₄ $\rightarrow$ Mg₃(PO₄)₂ + KCl

Question 22

Balance the equation
Sb(s) + O₂(g) $\rightarrow$ Sb₂O₃(s)

Question 23

Balance the equation
NaBH₄ + BF₃ $\rightarrow$ NaBF₄ + B₂H₆

Question 24

When table sugar is burned in air, carbon dioxide and water vapor are products, as shown by the following unbalanced chemical equation: C₁₂H₂₂O₁₁(s) + O₂(g) $\rightarrow$ CO₂(g) + H₂O(g)
How many moles of oxygen are required to react completely with 1.26 mol of sugar?

A) 15.1
B) 1.26
C) 22
D) 30
E) none of these

Question 25

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? NBr₃ + NaOH $\rightarrow$ N₂ + NaBr + HOBr

A) 1
B) 2
C) 3
D) 4
E) 5

Question 26

Balance the equation
KClO₃(s) $\rightarrow$ KCl(s) + O₂(g)

Question 27

When the following equations are balanced using the smallest possible integers, what is the number in front of the underlined substance in each case?

-S(s) + O₂(g) $\rightarrow$ SO₂(g)

A) 1
B) 2
C) 3
D) 4
E) 5

Question 28

Balance the equation
As₂O₃(s) + Ca(OH)₂(aq) $\rightarrow$ Ca₃(AsO₄)₂(s) + H₂O(l)

Question 29

When the following equations are balanced using the smallest possible integers, what is the number in front of the underlined substance in each case?

-Li(s) + O₂(g) $\rightarrow$ Li₂O(s)

A) 1
B) 2
C) 3
D) 4
E) 5

Question 30

When the following equations are balanced using the smallest possible integers, what is the number in front of the underlined substance in each case?

-Al₂O₃(s) + H₂SO₄(aq) $\rightarrow$ Al₂(SO₄)₃(aq) + H₂O(l)

A) 1
B) 2
C) 3
D) 6
E) 9

Question 31

When ethane (C₂H₆) is reacted with oxygen in the air, the products are carbon dioxide and water. This process requires __________ mol of oxygen for every 2.43 mol of ethane.

A) 8.51
B) 6.08
C) 2.43
D) 17.01
E) none of these

Question 32

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? KClO₃ $\rightarrow$ KCl + KClO₄

A) 1
B) 2
C) 3
D) 4
E) 5

Question 33

When the following equations are balanced using the smallest possible integers, what is the number in front of the underlined substance in each case?

-Pb(s) + AgNO₃(aq) $\rightarrow$ Pb(NO₃)₂ + Ag(s)

A) 1
B) 2
C) 4
D) 5
E) 6

Question 34

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? C₂H₆ + O₂ $\rightarrow$ CO₂ + H₂O

A) 1
B) 2
C) 4
D) 6
E) 7

Question 35

Balance the equation
C₆H₁₄ + O₂ $\rightarrow$ CO₂ + H₂O

Question 36

When the following equations are balanced using the smallest possible integers, what is the number in front of the underlined substance in each case?

-N₂(g) + O₂(g) $\rightarrow$ N₂O₃

A) 1
B) 2
C) 3
D) 4
E) 6

Question 37

When the following equations are balanced using the smallest possible integers, what is the number in front of the underlined substance in each case?

-C₂H₆(g) + O₂(g) $\rightarrow$ CO₂(g) + H₂O(g)

A) 4
B) 7
C) 8
D) 10
E) 14

Question 38

When the following equations are balanced using the smallest possible integers, what is the number in front of the underlined substance in each case?

-Sr(s) + P₄(s) $\rightarrow$ Sr₃P₂(s)

A) 2
B) 3
C) 6
D) 12
E) 18

Question 39

When the following equation is balanced using the smallest possible integers, what is the number in front of the substance in bold type? SiCl₄ + H₂O $\rightarrow$ SiO₂ + HCl

A) 1
B) 2
C) 3
D) 4
E) 5

Question 40

Balance the equation
Mg(OH)₂(aq) + 2HBr(aq) $\rightarrow$ MgBr₂(aq) + 2H₂O(l)

Question 41

Balance the equation
KI(aq) + Cl₂(g) $\rightarrow$ KCl(aq) + I₂(s)

Question 42

Balance the equation for the reaction of aluminum metal with solid iodine to form solid aluminum iodide.

Question 43

Write and balance the equation showing the reaction between iron(III) oxide and carbon monoxide to form iron metal and carbon dioxide.

Question 44

Balance the equation for the reaction of calcium metal with oxygen gas to produce solid calcium oxide.

Question 45

Balance the equation
Pb(NO₃)₂(aq) + K₂CrO₄(aq) $\rightarrow$ PbCrO₄(s) + KNO₃(aq)

Question 46

Balance the equation
Mg(s) + O₂(g) $\rightarrow$ MgO(s)

Question 47

Balance the equation for the reaction of potassium metal with water to form potassium hydroxide and hydrogen gas.

Question 48

When the following equations are balanced using the smallest possible integers, what is the number in front of the underlined substance in each case?

-C₄H₁₀(g) + O₂(g) $\rightarrow$ CO₂(g) + H₂O(g)

A) 2
B) 4
C) 6
D) 8
E) 10

Question 49

Balance the equation
H₂O₂(l) $\rightarrow$ H₂O(l) + O₂(g)

Question 50

Balance the equation
(NH₄)₂Cr₂O₇(s) $\rightarrow$ N₂(g) + H₂O(g) + Cr₂O₃(s)

Question 51

Write and balance the equation showing the reaction between iron(III) oxide and carbon monoxide to form iron(II) oxide and carbon dioxide.

Question 52

Balance the equation
BaCl₂(aq) + H₂SO₄(aq) $\rightarrow$ BaSO₄(s) + HCl(aq)

Question 53

Write and balance the equation showing the reaction between gaseous hydrogen sulfide and oxygen to form sulfur dioxide gas and water vapor.

Question 54

Which of the following statements about chemical reactions is false?

A) In balancing a chemical equation, all subscripts must be conserved.
B) When one coefficient is doubled, the rest of the coefficients in the balanced equation must also be doubled.
C) The subscripts in a balanced equation tell us the number of atoms in a molecule.
D) An individual coefficient in a balanced equation is meaningless.
E) The phases in a chemical reaction tell us the nature of the reactants and products.

Question 55

Write and balance the equation showing the reaction between nitrogen monoxide gas and hydrogen gas to form nitrogen gas and water vapor.

Question 56

Write and balance the equation showing the reaction between calcium metal and water to form aqueous calcium hydroxide and hydrogen gas.

Question 57

Write and balance the equation showing the reaction between copper metal and aqueous sulfuric acid to form aqueous copper(II) sulfate, sulfur dioxide gas, and water.

Question 58

When the following equations are balanced using the smallest possible integers, what is the number in front of the underlined substance in each case?

-Sb(s) + O₂(g) $\rightarrow$ Sb₂O₅(s)

A) 1
B) 2
C) 4
D) 6
E) 12

Question 59

Balance the equation
Zn(s) + HCl(aq) $\rightarrow$ H₂(g) + ZnCl₂(aq)

Question 60

When the following equations are balanced using the smallest possible integers, what is the number in front of the underlined substance in each case?

-CH₃OH(l) + O₂(g) $\rightarrow$ CO₂(g) + H₂O(g)

A) 1
B) 2
C) 4
D) 6
E) 12

Question 61

Balance the equation
Al(s) + S(s) $\rightarrow$ Al₂S₃(s)

Question 62

Balance the equation
C₈H₁₈(l) + O₂(g) $\rightarrow$ CO₂(g) + H₂O(g)

Question 63

Balance the equation
CaCO₃(s) + HCl(aq) $\rightarrow$ H₂O(l) + CO₂(g) + CaCl₂(aq)

Question 64

Balance the equation
K(s) + H₂O(l) $\rightarrow$ KOH(aq) + H₂(g)

Question 65

Balance the equation
HCl(aq) + Ca(OH)₂(aq) $\rightarrow$ CaCl₂(aq) + H₂O(l)

Question 66

Balance the equation
Ca(s) + O₂(g) $\rightarrow$ CaO(s)

Question 67

When the equation Si(s) + HF(aq) $\rightarrow$ SiF₄(g) + H₂(g) is balanced, what is the coefficient for HF?

A) 0
B) 1
C) 2
D) 3
E) 4

Question 68

Balance the equation
Mg₃N₂(s) + H₂O(l) $\rightarrow$ NH₃(g) + Mg(OH)₂(s)

Question 69

Balance the equation
Zn(s) + H₃PO₄(aq) $\rightarrow$ Zn₃(PO₄)₂(s) + H₂(g)

Question 70

Balance the equation
Na₂O(s) + H₂O(l) $\rightarrow$ NaOH(aq)

Question 71

Balance the equation
C₃H₇OH(l) + O₂(g) $\rightarrow$ CO₂(g) + H₂O(g)

Question 72

Balance the equation
Fe(NO₃)₂(aq) + H₂S(g) $\rightarrow$ FeS(s) + HNO₃(aq)

Question 73

Balance the equation
Na(s) + H₂O(l) $\rightarrow$ H₂(g) + NaOH(aq)

Question 74

Balance the equation
AgNO₃(aq) + CaCl₂(aq) $\rightarrow$ AgCl(s) + Ca(NO₃)₂(aq)

Question 75

Balance the equation
PBr₃(g) + H₂O(l) $\rightarrow$ H₃PO₃(aq) + HBr(aq)

Question 76

Balance the equation
NH₃(g) + O₂(g) $\rightarrow$ NO(g) + H₂O(l)