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Worksheets

Chemical Reactions and pH Review

Total questions: 59

Worksheet time: 30mins

Name
Class
Date
1.

What does the pH scale measure?

a)

Temperature

b)

Concentration of H+ ions

c)

Number of atoms in a molecule

d)

Amount of dissolved solids

2.

A solution with a pH of 2 is best described as...

a)

Neutral

b)

Acid

c)

Base

3.

A solution with a pH of 7 is...

a)

Neutral

b)

Acid

c)

Base

4.

As pH decreases, the concentration of H+ ions...

a)

Increases

b)

Stays the same

c)

Decreases

d)

Changes randomly

5.

Which of the following pH values is the most basic?

a)

1

b)

4

c)

6

d)

10

6.

If a solution changes from a pH 6 to a pH 4, it becomes...

a)

10X more acidic

b)

100X more acidic

c)

10X more basic

d)

100X more basic

7.

Which of these is an acid?

a)

Baking soda

b)

Soap

c)

Lemon juice

d)

Water

8.

The pH scale ranges from...

a)

-5 to 5

b)

0 to 14

c)

1 to 100

d)

-14 to 14

9.

What ion is found in basic solutions?

a)

H+

b)

OH-

c)

Na+

d)

Cl-

10.

What is an element?

a)

A pure substance made of only one kind of atom.

b)

A substance made of two atoms bonded together.

c)

A mixture of multiple compounds.

d)

A molecule made of different elements.

11.

Which of the following is a molecule? (Select all that apply)

a)

O₂

b)

CO₂

c)

NaCl

d)

Fe

12.

What is a compound?

a)

A pure substance made of two or more different elements chemically bonded.

b)

A mixture of elements physically combined.

c)

A single atom.

d)

A molecule made of the same element.

13.

Which formulas represent elements? (Select all that apply)

a)

He

b)

N₂

c)

H₂O

d)

CO₂

14.

Which formulas represent compounds? (Select all that apply)

a)

H₂O

b)

NaCl

c)

O₃

d)

Fe

15.

Which of the following is NOT a sign of a chemical reaction?

a)

Change in temperature

b)

Change in color

c)

Gas production

d)

Melting ice cube

16.

What does a subscript represent?

a)

The number of atoms of that element.

b)

The number of molecules.

c)

The coefficient.

d)

The charge.

17.

Which are signs of a chemical reaction? (Select all that apply)

a)

Odor change

b)

Temperature change

c)

Dissolving sugar

d)

Production of a solid (precipitate)

18.

What is the reactant side of a chemical equation?

a)

The starting substances before the reaction.

b)

The substances formed after the reaction.

c)

The subscript.

d)

The catalyst.

19.

What is the product side of a chemical equation?

a)

The substances formed by the reaction.

b)

The substances that are used up.

c)

Only gases.

d)

Only solids.

20.

What type of reaction is A + B → AB?

a)

Decomposition

b)

Synthesis

c)

Single replacement

d)

Combustion

21.

What type of reaction is AB → A + B?

a)

Synthesis

b)

Single replacement

c)

Decomposition

d)

Double replacement

22.

What type of reaction is AB + C → AC + B?

a)

Synthesis

b)

Single replacement

c)

Double replacement

d)

Decomposition

23.

What type of reaction is AB + CD → AD + CB?

a)

Single replacement

b)

Double replacement

c)

Decomposition

d)

Synthesis

24.

Which reaction shows a synthesis reaction?

a)

2H₂ + O₂ → 2H₂O

b)

2KClO₃ → 2KCl + 3O₂

c)

Cu + AgNO₃ → Ag + CuNO₃

d)

Pb(NO₃)₂ + KI → KNO₃ + PbI₂

25.

Which reaction shows a decomposition reaction?

a)

Ca + Cl₂ → CaCl₂

b)

2HgO → 2Hg + O₂

c)

Mg + HCl → MgCl₂ + H₂

d)

NaCl + AgNO₃ → AgCl + NaNO₃

26.

Which reaction shows a single replacement reaction?

a)

Zn + HCl → ZnCl₂ + H₂

b)

H₂ + O₂ → H₂O

c)

NaOH + HCl → NaCl + H₂O

d)

CaCO₃ → CaO + CO₂

27.

Which of the following is a chemical change?

a)

Burning wood

b)

Boiling water

c)

Breaking a rock

d)

Melting ice

28.

Which reaction produces a precipitate?

a)

A solid forms in a solution.

b)

Water boils.

c)

Ice melts.

d)

Gas bubbles form.

29.

Which reaction shows gas production?

a)

Formation of bubbles

b)

Color change

c)

Temperature change

d)

A solid appears

30.

Identify the products in: Na + Cl₂ → NaCl

a)

Na

b)

Cl₂

c)

NaCl

31.

Identify the reactants in: C + O₂ → CO₂

a)

CO₂

b)

C

c)

O₂

32.

What does the arrow (→) mean in a chemical equation?

a)

Reacts to produce

b)

Is equal to

c)

Forms a mixture

d)

Means the reaction is reversible

33.

Identify the reaction type: CaCO₃ → CaO + CO₂

a)

Synthesis

b)

Decomposition

c)

Single replacement

d)

Double replacement

34.

Identify the reaction type: Ca + 2HCl → CaCl₂ + H₂

a)

Double replacement

b)

Synthesis

c)

Single replacement

d)

Decomposition

35.

Identify the reaction type: AgNO₃ + NaCl → AgCl + NaNO₃

a)

Double replacement

b)

Single replacement

c)

Synthesis

d)

Decomposition

36.

Is the equation balanced? H₂ + Cl₂ → 2HCl

a)

Yes

b)

No

37.

Is the equation balanced? N₂ + H₂ → 2NH₃

a)

Yes

b)

No

38.

Is the equation balanced? 2Mg + O₂ → 2MgO

a)

Yes

b)

No

39.

Is the equation balanced? Fe + O₂ → Fe₂O₃

a)

Yes

b)

No

40.

Which shows a color change due to a chemical reaction?

a)

Iron rusting

b)

Red dye dissolving in water

c)

Melting chocolate

d)

Freezing water

41.

Which represents a balanced equation?

a)

2H₂ + O₂ → 2H₂O

b)

H₂ + O₂ → H₂O

c)

Fe + O₂ → Fe₂O₃

d)

N₂ + H₂ → NH₃

42.

Which represents an unbalanced equation? (Select all that apply)

a)

H₂ + O₂ → H₂O

b)

N₂ + 3H₂ → 2NH₃

c)

Fe + O₂ → Fe₂O₃

d)

2Mg + O₂ → 2MgO

43.

Which best describes a precipitate?

a)

A solid formed from a solution during a reaction.

b)

A gas released.

c)

A liquid evaporating.

d)

A color change.

44.

Identify the reaction: 2K + Br₂ → 2KBr

a)

Synthesis

b)

Decomposition

c)

Single replacement

d)

Double replacement

45.

Identify the reaction: Cu + 2AgCl → 2Ag + CuCl₂

a)

Double replacement

b)

Single replacement

c)

Synthesis

d)

Decomposition

46.

Identify the reaction: BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl

a)

Double replacement

b)

Single replacement

c)

Synthesis

d)

Decomposition

47.

What happens to atoms during a chemical reaction?

a)

Bonds between atoms are broken and made to form new substances.

b)

The atoms disappear.

c)

They turn into energy.

d)

They gain mass.

48.

Which of the following is an example of a compound?

a)

CO₂

b)

O₂

c)

Ni

d)

Ne

49.

Which shows evidence a chemical reaction occurred? (Select all that apply)

a)

Gas production

b)

Temperature change

c)

A new solid forms

d)

Boiling water

50.

What does a coefficient represent?

a)

Number of molecules or formula units

b)

Number of atoms

c)

Charge

d)

Subscript

51.

Which represents a physical change?

a)

Ice melting

b)

Wood burning

c)

Rust forming

d)

Baking bread

52.

What must remain the same on both sides of a chemical equation?

a)

Number of each type of atom

b)

Number of molecules

c)

Temperature

d)

Volume

53.

Identify the reactants in: Mg + O₂ → MgO

a)

Mg

b)

O₂

c)

MgO

54.

Identify the products in: H₂ + Cl₂ → 2HCl

a)

H₂

b)

Cl₂

c)

HCl

55.

Balance: H₂ + O₂ → H₂O

a)

2,1,2

b)

1,1,2

c)

2,2,1

d)

1,2,2

56.

Balance: N₂ + H₂ → NH₃

a)

1,3,2

b)

1,1,2

c)

2,3,2

d)

1,2,3

57.

Balance: Fe + O₂ → Fe₂O₃

a)

4,3,2

b)

1,1,1

c)

2,2,3

d)

3,2,4

58.

Balance: Mg + O₂ → MgO

a)

2,1,2

b)

1,1,1

c)

1,2,1

d)

3,1,3

59.

Balance: Al + O₂ → Al₂O₃

a)

4,3,2

b)

1,1,1

c)

2,1,1

d)

1,2,3