Free Printable C12 Balancing Reactions

1.

How many CARBON atoms are in the following?

$3C_2H_5O$

2.

How many HYDROGEN atoms are in the following?

$3C_2H_5O$

3.

How many OXYGEN atoms are in the following?

$3C_2H_5O$

4.

What is the missing coefficient?

$2KClO_3\ \rightarrow\ 2KCl+\ ??O_2$

5.

What is the missing coefficient?

$2KClO_3\ \rightarrow\ ??KCl\ +\ 3O_2$

6.

What is the missing coefficient?

$3Fe\ +\ ??O_2\ \rightarrow\ Fe_3O_4$

7.

What is the missing coefficient?

$??Fe\ +\ 2O_2\ \rightarrow\ Fe_3O_4$

8.

What is the missing coefficient?

$??NH_4NO_3\ +\ Ca_3\left(PO_4\right)_2\ \rightarrow\ 2\left(NH_4\right)_3PO_4\ +\ 3Ca\left(NO_3\right)_2$

9.

_P₄+_O₂→ _P₂O₃

a)

3 P₄+ O₂→ 2 P₂O₃

b)

P₄+ O₂→ 2 P₂O₃

c)

P₄+ 3 O₂→ 2 P₂O₃

d)

P₄+ 2 O₂→ 3 P₂O₃

10.

_AgNO₃ + _Cu →_Cu(NO₃)₂ + _Ag

a)

2, 2, 3, 1

b)

2, 1, 1, 2

c)

1, 2, 2, 1

d)

3, 2, 3, 2

11.

_BaS + _PtF₂ → _BaF₂ + _PtS

a)

1 : 1 : 1 : 1

b)

4 : 2 : 1 : 1

c)

1 : 2 : 2 : 2

d)

1 : 3 : 1 : 2

12.

_AlBr₃ + _K₂SO₄→ _KBr + _Al₂(SO₄)₃

a)

6 AlBr₃ + K₂SO₄ → 6 KBr + Al₂(SO₄)₃

b)

2 AlBr₃ + 3 K₂SO₄→ 6 KBr + Al₂(SO₄)₃

c)

AlBr₃ + K₂SO₄→ 2 KBr + 3 Al₂(SO₄)₃

d)

2 AlBr₃ + 3 K₂SO₄→ KBr + 2 Al₂(SO₄)₃

13.

_SO₂ + _Li₂Se →_SSe₂ + _Li₂O

a)

1, 2, 1, 2

b)

1, 1, 2, 2

c)

2, 2, 2, 2

d)

2, 2, 1, 1

e)

2, 1, 2, 1

14.

_Al + _HCl →_H₂ + _AlCl₃

a)

2 : 2 : 2 : 6

b)

3 : 3 : 6 : 2

c)

1 : 1 : 3 : 1

d)

2 : 6 : 3 : 2

15.

_K + _Cl₂ →_KCl

a)

2 K + 16 Cl₂ → 8 KCl

b)

2 K + Cl₂ → 2 KCl

c)

3 K + 4 Cl₂ → 3 KCl

d)

K + Cl₂ →KCl

16.

_NaF + _Br₂ →_NaBr + _F₂

a)

1 : 2 : 1 : 2

b)

2 : 2 : 2 : 2

c)

2 : 3 : 1 : 2

d)

2 : 1 : 2 : 1

17.

Balance this equation, Al₂O₃ ---> Al + O₂

a)

Cannot be balanced

b)

2Al₂O₃ ---> 2Al + 3O₂

c)

2Al₂O₃ ---> 4Al + 3O₂

d)

3Al₂O₃ ---> 2Al + O₂

18.

Balance this equation: H₂ + N₂ → NH₃

a)

H₂ + 4N₂ → NH₃

b)

H₂ + 3N₂ → 2NH₃

c)

3H₂ + N₂ → 2NH₃

d)

2H₂ + 2N₂ → 2NH₃

19.

Substances that enter into a chemical reaction (found to the left side of the arrow)

a)

product

b)

reactant

c)

chemical

d)

balanced equation

20.

The large number in front of a chemical formula or compound is the ___________.

a)

coefficient

b)

product

c)

physical

d)

chemical

21.

Is the following equation balanced or unbalanced?
Fe + S --> FeS

a)

balanced

b)

unbalanced

22.

What is the part of the chemical equation in green called?
Fe + S --> FeS

a)

products

b)

reactants

c)

yield

d)

chemical formula

23.

How many atoms of aluminum are on each side of the following equation: 4Al + 3O₂--> 2Al₂O₃

a)

2

b)

6

c)

1

d)

4

24.

___________________ are the elements or compounds that are formed in a chemical
reaction.

a)

Polymers

b)

Bonds

c)

Reactants

d)

Products

25.

What is/are the REACTANT(S) in the reaction shown?

$NaCl\ +\ H_2SO_4\ \rightarrow\ Na_2SO_4\ +\ HCl$

Mark all that apply.

a)

NaCl

b)

H₂SO₄

c)

Na₂SO₄

d)

HCl

26.

What is/are the PRODUCT(S) in the reaction shown?

$NaCl\ +\ H_2SO_4\ \rightarrow\ Na_2SO_4\ +\ HCl$

Mark all that apply.

a)

NaCl

b)

H₂SO₄

c)

Na₂SO₄

d)

HCl

27.

What is/are the REACTANT(S) in the reaction shown?

$\left(NH_4\right)_2\ CO_3\ \rightarrow\ NH_3+\ H_2O\ +\ CO_2$

Mark all that apply.

a)

(NH₄)₂CO₃

b)

NH₃

c)

H₂O

d)

CO₂

28.

What is/are the PRODUCT(S) in the reaction shown?

$\left(NH_4\right)_2\ CO_3\ \rightarrow\ NH_3+\ H_2O\ +\ CO_2$

Mark all that apply.

a)

(NH₄)₂CO₃

b)

NH₃

c)

H₂O

d)

CO₂

29.

Match the phase symbol with the phase it represents.

a)

(g)

1.

gas

b)

(l)

2.

liquid

c)

(s)

3.

solid

d)

(aq)

4.

aqueous

30.

Match the phase symbol with the substance that would use it in a reaction.

a)

(g)

1.

helium

b)

(l)

2.

molten NaCl

c)

(s)

3.

dry ice

d)

(aq)

4.

salt water solution

31.

What scientific law requires that chemical reactions be balanced?

The Law of (a)

32.

What scientific law requires that the same type and number of atoms must remain constant during a chemical reaction?

The Law of (a)

33.

What scientific law requires that mass of the products must be the same as the mass of the reactants?

(a)

34.

(a) PbO₂ → (b) PbO + (c) O₂

Choose from the below words

2

1

0

3

4

5

35.

(a) Fe(OH)₃ → (b) Fe₂O₃ + (c) H₂O

Choose from the below words

2

1

3

0

4

5

36.

(a) (NH₄)₂CO₃ → (b) NH₃ + (c) H₂O + (d) CO₂

Choose from the below words

1

2

0

4

5

3

37.

Balance the reaction:

(a) NaCl + (b) H₂SO₄ → (c) Na₂SO₄ + (d) HCl

Choose from the below words

2

1

0

3

4

5

38.

Balance the reaction:

(a) NH₃ + (b) O₂ → (c) NO + (d) H₂O

Choose from the below words

4

5

6

0

1

2

3

39.

(a) Mg + (b) H₂SO₄ → (c) MgSO₄ + (d) H₂

Choose from the below words

1

2

3

4

5

6

7

0

8

9

40.

Balance the reaction:

(a) C₃H₈ + (b) O₂ → (c) CO₂ + (d) H₂O

Choose from the below words

1

5

3

4

2

6

7

8

9

10

41.

Balance the reaction:

(a) C₆H₁₂O₆ + (b) O₂ → (c) CO₂+ (d) H₂O

Choose from the below words

1

6

2

12

4

3

18

8

16

14

42.

Balance the reaction:

(a) Al_(s)+ (b) ZnCl_{2 (aq)} → (c) Zn_(s)+ (d) AlCl₃ _(aq)

Choose from the below words

2

3

1

4

6

5

8

12

9

7

43.

Which of the following substances are SOLUBLE in water?

Al_(s)+ ZnCl_{2 (aq)} → Zn_(s)+ AlCl₃ _(aq)

a)

Al

b)

ZnCl₂

c)

Zn

d)

AlCl₃

44.

Which of the following substances are INSOLUBLE in water?

Al_(s)+ ZnCl_{2 (aq)} → Zn_(s)+ AlCl₃ _(aq)

a)

Al

b)

ZnCl₂

c)

Zn

d)

AlCl₃

45.

Balance the reaction:

(a) S _(s)+ (b) O_{2 (g)}→ (c) SO_{3 (g)}

Choose from the below words

2

3

1

0

4

5

6

7

8

9

46.

If the reaction below were performed in an OPEN reaction vessel on an electronic balance, what would happen to the mass?

2S _(s)+ 3O_{2 (g)}→ 2SO_{3 (g)}

a)

mass would increase

b)

mass would decrease

c)

mass would stay the same

47.

If the reaction below were performed in an OPEN reaction vessel on an electronic balance, what would happen to the mass?

2S _(s)+ 3O_{2 (g)}→ 2SO_{3 (s)}

a)

mass would increase

b)

mass would decrease

c)

mass would stay the same

48.

If the reaction below were performed in an open vessel on an electronic balance, the mass decreases because the product is a gas and escapes to the environment. Does this violate the Law of Conservation of Mass?

2S _(s)+ 3O_{2 (g)}→ 2SO_{3 (g)}

a)

Yes, mass cannot change in a chemical reaction.

b)

No, the total mass does not change. The product is lost to the atmosphere and is not weighed.

49.

(a) HgO _(s) → (b) Hg₍_l₎ + (c) O_{2 (g)}

Choose from the below words

2

1

3

4

5

6

7

8

0

9

50.

If the below reaction were performed in a CLOSED and sealed bottle on an electronic balance, what would happen to the mass?

HgO _(s) → Hg₍_l₎ + O_{2 (g)}

a)

mass would decrease

b)

mass would increase

c)

mass would stay constant

51.

If the below reaction were performed in an OPEN bottle on an electronic balance, what would happen to the mass?

HgO _(s) → Hg₍_l₎ + O_{2 (g)}

a)

mass would decrease

b)

mass would increase

c)

mass would stay constant

52.

If the reaction below were performed in a SEALED reaction vessel on an electronic balance, what would happen to the mass?

2S _(s)+ 3O_{2 (g)}→ 2SO_{3 (g)}

a)

mass would increase

b)

mass would decrease

c)

mass would stay the same

53.

Balance the reaction:

(a) P_(s) + (b) O_{2 (g)} → (c) P₂O_{5 (s)}

Choose from the below words

4

5

2

1

3

6

7

8

9

10

54.

If the reaction below were performed in an OPEN reaction vessel on an electronic balance, what would happen to the mass?

4P_(s) + 5O_{2 (g)} → 2P₂O_{5 (s)}

a)

mass would increase

b)

mass would decrease

c)

mass would stay constant

55.

If the reaction below were performed in an OPEN reaction vessel on an electronic balance, what would happen to the mass?

4P_(s) + 5C_(s) → P₄C_{5 (s)}

a)

mass would increase

b)

mass would decrease

c)

mass would stay constant

56.

If the reaction below were performed in an OPEN reaction vessel on an electronic balance, what would happen to the mass?

4P_(s) + 5C_(s) → P₄C_{5 (g)}

a)

mass would increase

b)

mass would decrease

c)

mass would stay constant

57.

Balance the reaction:

(a) C₂H₆ + (b) O₂ → (c) CO₂ + (d) H₂O

Choose from the below words

2

7

4

6

3

1

5

8

9

10

58.

Balance the reaction:

(a) C₄H₁₀ + (b) (c) O₂ → (d) CO₂ + (e) H₂O

Choose from the below words

2

1

3

8

10

5

9

4

6

7

59.

Balance the reaction:

(a) C₆H₁₄ + (b) O₂ → (c) CO₂ + (d) H₂O

Choose from the below words

2

19

12

14

5

4

6

7

1

9

60.

Balance the reaction:

(a) C₃H₈ + (b) O₂ → (c) CO₂ + (d) H₂O

Choose from the below words

1

5

3

4

8

9

10

2

6

7

61.

Balance the reaction:

(a) C₅H₁₂ + (b) O₂ → (c) CO₂ + (d) H₂O

Choose from the below words

1

8

5

6

9

10

2

7

3

4

62.

Balance the reaction:

(a) C₇H₁₆ + (b) O₂ → (c) CO₂ + (d) H₂O

Choose from the below words

1

11

7

8

9

10

2

3

4

5

63.

Balance the reaction:

(a) Fe₂O₃ + (b) Al → (c) Al₂O₃ + (d) Fe

Choose from the below words

1

2

3

4

5

6

7

8

9

0

64.

Balance the reaction:

(a) KOH + (b) H₂CO₃ → (c) K₂CO₃ + (d) H₂O

Choose from the below words

2

1

3

4

5

6

7

8

9

10

65.

Balance the reaction:

(a) Al(OH)₃ + (b) H₂SO₄ → (c) Al₂(SO₄)₃ + (d) H₂O

Choose from the below words

2

3

1

6

4

5

7

8

9

10

66.

Balance the reaction:

(a) Mg(OH)₂ + (b) H₃PO₄ → (c) Mg₃(PO₄)₂ + (d) H₂O

Choose from the below words

3

2

1

6

4

5

7

8

9

10

67.

Balance the reaction:

(a) Ca(OH)₂ + (b) H₂SO₄ → (c) CaSO₄ + (d) H₂O

Choose from the below words

1

2

3

4

5

6

7

8

9

10

68.

(a) NaOH + (b) H₂CrO₇ → (c) Na₂CrO₇ + (d) H₂O

Choose from the below words

2

1

3

4

5

6

7

8

9

10

69.

(a) K + (b) F₂ → (c) KF

Choose from the below words

2

1

0

3

4

5

70.

(a) Li + (b) Br₂ → (c) LiBr

Choose from the below words

2

1

0

3

4

5

71.

Balance the reaction:

(a) Ba + (b) I₂ → (c) BaI₂

Choose from the below words

1

0

2

4

3

5

72.

Balance the reaction:

(a) Ba + (b) O₂ → (c) BaO

Choose from the below words

2

1

0

4

3

5

73.

Balance the reaction:

(a) Ca + (b) S → (c) CaS

Choose from the below words

1

0

2

4

3

5

74.

(a) Rb + (b) O₂ → (c) Rb₂O

Choose from the below words

4

1

2

3

0

5

75.

(a) Cs + (b) S → (c) Cs₂S

Choose from the below words

2

1

3

0

5

4

76.

If the reaction below is performed in an OPEN reaction vessel on an electronic balance, what will happen to mass?

2Cs _(s) + S _(s) → Cs₂S _(s)

a)

mass will increase

b)

mass will decrease

c)

mass will stay constant

77.

If the reaction shown is performed in an OPEN reaction vessel, what will happen to the mass?

2Ba_(s) + O_{2 (g)} → 2BaO_(s)

a)

mass will increase

b)

mass will decrease

c)

mass will stay constant

78.

If the reaction below is performed in an OPEN reaction vessel on an electronic balance, what will happen to mass?

2Cs _(s) + S _(s) → Cs₂S _(s)

a)

mass will increase

b)

mass will decrease

c)

mass will stay constant

79.

Balance the reaction:

(a) F₂ + (b) CoCl₃→ (c) CoF₃ + (d) Cl₂

Choose from the below words

3

2

1

0

4

5

80.

How many OXYGEN atoms are in the following?

$2Al_2\left(SO_4\right)_3$

81.

How many SULFUR atoms are in the following?

$2Al_2\left(SO_4\right)_3$

82.

How many ALUMINUM atoms are in the following?

$2Al_2\left(SO_4\right)_3$

83.

Which of these VIOLATES the Law of Conservation of Mass? Why?

(Pick one reaction, pick one reason)

a)

the reaction is NOT balanced

b)

the reaction is balanced

c)

H₂ + O₂ → H₂O

d)

2Na + Cl₂ → 2NaCl

84.

Which of these reactions FOLLOW the Law of Conservation of Mass? Why?

(Pick one reaction, pick one reason)

a)

the reaction is NOT balanced

b)

the reaction is balanced

c)

H₂ + O₂ → H₂O

d)

2Na + Cl₂ → 2NaCl

85.

Which of these reactions VIOLATES the Law of Conservation of Mass? Why?

(Pick one reaction, pick one reason)

a)

the reaction is NOT balanced

b)

the reaction is balanced

c)

2H₂ + O₂ → 2H₂O

d)

Na + Cl₂ → NaCl

86.

What type of reaction violates the Law of Conservation of Mass?

a)

an unbalanced reaction

b)

a balanced reaction

87.

What type of reaction follows the Law of Conservation of Mass?

a)

an unbalanced reaction

b)

a balanced reaction

88.

The reaction is balanced but INCORRECT. What is wrong with the reaction?

$Cl_2\ +\ NaI\ \rightarrow\ NaCl_2\ +\ I$

a)

Cl₂should be Cl

b)

NaI should be NaI₂

c)

NaCl₂ should be NaCl

d)

I should be I₂

e)

nothing wrong

89.

The reaction is balanced but INCORRECT. What is wrong with the reaction?

$NH_3\ \rightarrow\ N\ +\ H_3$

a)

NH₃ should be NH₄

b)

N should be N₂

c)

H₃ should be H

d)

H₃ should be H₂

e)

nothing wrong

90.

The reaction is balanced but INCORRECT. What is wrong with the reaction?

$Na\ +\ O_2\ \rightarrow\ NaO_2$

a)

Na should be Na₂

b)

O₂ should be O

c)

NaO₂ should be NaO

d)

NaO₂ should be Na₂O

e)

nothing wrong with this reaction

91.

The reaction is balanced but INCORRECT. What is wrong with the reaction?

$H_2\ +\ Cl_2\ \rightarrow\ H_2Cl_2$

a)

Cl₂ should be Cl

b)

H₂ should be H

c)

H₂Cl₂ should be HCl

d)

H₂Cl₂should be HCl₂

e)

nothing wrong with this reaction

92.

The reaction is balanced but INCORRECT. What is wrong with the reaction?

$2Mg\ +\ H_2SO_4\ \rightarrow\ Mg_2SO_4\ +\ H_2$

a)

Mg should be Mg₂

b)

H₂SO₄ should be HSO₄

c)

H₂ should be H

d)

Mg₂SO₄ should be MgSO₄

e)

Mg₂SO₄ should be Mg(SO₄)₂

93.

$3XY\ +\ 2AB\ \rightarrow\ XB\ +\ 4AY$

If 24 g of XY completely reacts with 20 g of AB what will the mass of the products be?