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Chemistry 9

Total questions: 28

Worksheet time: 1hrs 4mins

Name
Class
Date
1.

In which substance does sulfur have a negative oxidation number?

a)

S

b)

Na2S

c)

CaSO4

d)

SO2

2.

Given the electrochemical cell reaction:

Zn(s) + Ni2+ (aq) → Zn2+ (aq) + Ni(s)

Which species is the reducing agent?

a)

Ni2+

b)

Zn

c)

Zn2

d)

Ni

3.

In a redox reaction, the species reduced

a)

gains electrons and is the oxidizing agent

b)

loses electrons and is the oxidizing agent

c)

loses electrons and is the reducing agent

d)

gains electrons and is the reducing agent

4.

Which half-reaction correctly represents reduction?

a)

S2– → S + 2e–

b)

Mn7+ + 3e– → Mn4+

c)

Mn7+ → Mn4+ + 3e–

d)

S2– + 2e– → S

5.

In the reaction

2Ca(s) + O2(g) --> 2CaO(s), calcium is __________

a)

Reduced

b)

Synthesized

c)

None of the above

d)

Oxidized

6.

In the reaction Zn + H2O --> ZnO2 + H2

which element, if any, is oxidized?

a)

Zinc

b)

Oxygen

c)

Hydrogen

d)

None

7.

What substance is oxidized in the following reaction?

4Fe + 3O2 --> 2Fe2O3

a)

Iron

b)

Fluorine

c)

Oxygen

d)

None

8.

If in a reaction, copper is reduced; its number of electrons has:

a)

Increased

b)

Remained Constant

c)

Decreased

d)

Varies Randomly

9.

What element is being Oxidized?

a)

N

b)

O

c)

H

d)

S

10.

Pollution _________________________.

a)

is harmful materials put into the environment

b)

found in air, water, and land

c)

effects plants, animals, and people

d)

All of the above

11.

Smog is an example of ______________ pollution.

a)

land

b)

water

c)

air

d)

noise

12.

How does air pollution effect people?

a)

It can cause people to have difficulty breathing.

b)

It can make sick people even sicker.

c)

All of the above

d)

Sometimes, air pollution can cause cancer.

13.

'Have you ever eaten sherbet sweets? They fizz in your mouth and your tongue feels cold. Why do you think that is?'

a)

It is an exothermic reaction

b)

It is an endothermic reaction

c)

It is made of ice

d)

It is dissolving your mouth

14.

Which of the following is a sign that a chemical reaction has occurred?

a)

change in shape

b)

melting

c)

bubbles of gas appear

d)

dissolving

15.

Which statement is correct?

a)

H2SO3 is reducing agent because it undergoes reduction.

b)

Sn4+ is oxidizing agent because it undergoes oxidation

c)

Sn4+ is reducing agent because it undergoes oxidation

d)

H2SO3 is reducing agent because it undergoes oxidation.

16.

For the balanced equation shown below

4Fe + 3O2 --> 2Fe2O3

What is the mass of O2

a)

96g

b)

16g

c)

32g

d)

22g

17.

Given the equation:

2NaClO3 (s) → 2NaCl (s) + 3O2 (g)

2.00 moles of NaClO3 will produce how many grams of O2? (mass of O2 = 32g/mol)

a)

56 g of O2

b)

96 g of O2

c)

64 g O2

d)

32 g O2

18.

2Na + 2H2O → 2NaOH+ H2

How many grams of hydrogen are produced if 120 g of Na are available?

a)

5.27 g

b)

2.6 g

c)

45 g

d)

690 g

19.

2Al + 3H2SO4 -> Al2(SO4)3 + 3H2

How many grams of aluminum sulfate would be formed if 250g H2SO4 completely reacted with aluminum?

a)

290 g

b)

0.85 g

c)

870 g

d)

450 g

20.

If 15 grams of copper (II) chloride react with 20 grams of sodium nitrate, how much sodium chloride can be formed? ( Limiting )

a)

13.04 g

b)

130.4 g

c)

10.34 moles

d)

13.04 moles

21.

How many grams of ammonia (NH3) can be produced from the reaction of 28 g of nitrogen gas and 25 grams of hydrogen gas?

a)

43 grams

b)

34 grams

c)

25 grams

d)

34 moles

22.

What is a limiting reactant?

a)

the reactant that determines how much product can be made

b)

the reactant that is in excess

c)

the product that you can make the most of

d)

the amount of reactants that react with each other

23.

2Fe2O3 + C → Fe + 3CO2

You add 28 grams of carbon. You find the actual yield to be 181.2 grams of CO2. What is the percent yield of CO2? (Hint: calculate theoretical yield of CO2 first)

a)

15.8%

b)

29.2%

c)

35%

d)

15.5%

24.

CH4 + 2O2 → CO2 + 2H2O

24 grams of CH4 was added to the above reaction. Calculate the theoretical yield of CO2.

a)

66 grams

b)

132 grams

c)

8.72

d)

8.72

25.

When reacting Na with Cl2, we calculated that the theoretical yield should be 13 grams. Our actual yield was 12.5 grams. What is the percent yield?

a)

90.4%

b)

104%

c)

1.04%

d)

96.15%

26.

How can trash effect wildlife?

a)

Wildlife animals cannot hunt prey because of the smell of garbage.

b)

Wildlife could eat trash that they think is food.

c)

Trash makes it hard for wildlife to camouflage.

d)

Wildlife animals are afraid of trash.

27.

What are the main sources of water pollution?

a)

Plastic, Paper, and Metal

b)

Snails in water

c)

Help, there is a boot with a snake inside of it that somehow in the nearby lake.

d)

Agriculture, Industry, and Community

28.

Which of the following is not a natural cause of water pollution?

a)

Volcanoes

b)

Oil spills

c)

Animal waste

d)

Silt from storms and floods