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Chemical Reactions Quiz

Total questions: 49

Worksheet time: 2hrs 40mins

Name
Class
Date
1.

Which of the following is a balanced chemical equation?

a)

N₂ + O₂ → 2N₂O

b)

2Al + 3NiBr₂ → 2AlBr3 + 3Ni

c)

KI + Cl₂ → 2KCl + I₂

d)

All the above are balanced chemical equations.

2.

How many moles of ammonia are produced by the following reaction?

a)

1

b)

2

c)

3

d)

6

3.

Which of the following are evidences of a chemical change?

a)

A precipitate forms.

b)

Bubbles form.

c)

A change in color occurs.

d)

A change in phase from a liquid to a gas occurs.

e)

A change in temperature occurs.

4.

A combination of chemical formulas and symbols that models a chemical reaction is a(n) chemical equation.

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5.

The mass of one mole of a substance is its molar mass.

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6.

What kind of reaction occurs when water breaks up into hydrogen and oxygen gas?

a)

decomposition

b)

double-replacement

c)

single-replacement

d)

synthesis

7.

What kind of reaction is Ba + 2HCl → BaCl₂ + H₂?

a)

decomposition

b)

double-replacement

c)

single-replacement

d)

synthesis

8.

The term oxidation is used today to refer to

a)

any reaction that burns.

b)

any reaction where electrons are lost.

c)

fuel reacting with oxygen.

d)

reactions between metals and oxygen.

9.

(True or False) Oxygen must be present for a combustion reaction to occur.

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10.

(True or False) Oxygen must be present for an oxidation reaction to occur.

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11.

To produce iron(II) sulfide, which element goes through oxidation? Which element goes through reduction?

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12.

Chemical reactions that give off heat are called

a)

catalytic

b)

conservation

c)

endothermic

d)

exothermic

13.

(True or False) The energy needed to get a chemical reaction started is called catalyst energy.

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14.

(True or False) Endothermic reactions create energy.

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15.

What is the law of conservation of energy?

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16.

Which of the following is not part of the collision model for affecting reaction rates?

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17.

Which of the following would most likely increase the reaction rate of a chemical reaction?

a)

Catalysts must be present to increase the reaction rate.

b)

Enough energy must be present.

c)

Reactant particles must be aligned properly.

d)

Reactant particles must collide.

18.

Which of the following decreases the rate of a reaction?

a)

a catalyst

b)

an enzyme

c)

an inhibitor

d)

a reduction

19.

(True or False) When a system reaches chemical equilibrium, the forward and reverse reactions stop.

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20.

(True or False) According to Le Châtelier's principle, systems in equilibrium cannot be changed.

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21.

Predict what would happen to the system in equilibrium given by the equation 2Na+ 2H₂O = 2NaOH + H₂ if (1) water were added or (2) the temperature were decreased. The forward reaction is exothermic.

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22.

Which of the following is not evidence that a chemical change has occurred?

a)

a change in color

b)

a change in size

c)

a distinct smell

d)

a change in temperature

23.

Identify the correctly balanced chemical equation for the following word equation: Magnesium metal burns in gaseous oxygen to produce magnesium oxide.

a)

Mg + O₂ → 2MgO2

b)

2Mg + O₂ → 2MgO2

c)

2Mg + O2MgO

d)

2Mg + 20₂ → 2MgO₂

24.

What is a mole?

a)

an equation

b)

a mass

c)

a quantity

d)

a ratio

25.

How many moles of hydrogen gas are needed for the following reaction? N₂ + 3H₂ → 2NH3

a)

1

b)

2

c)

3

d)

6

26.

A key feature of a single-replacement reaction is that

a)

a single reactant becomes two or more products.

b)

both reactants and products include an element and a compound.

c)

two compounds swap ions, producing two new compounds.

d)

two or more reactants become a single product.

27.

Which of the following occur(s) in a redox reaction?

a)

An element loses electrons.

b)

An element gains electrons.

c)

both A and B

d)

neither A nor B

28.

Which of the following reactions require(s) the presence of oxygen?

a)

combustion

b)

oxidation

c)

both A and B

d)

neither A nor B

29.

Which of the following does not happen to the energy given off by a campfire?

a)

Some energy is absorbed by the environment.

b)

Some energy is given off as light energy.

c)

Some energy is given off as thermal energy.

d)

Some energy is destroyed by combustion.

30.

How does a catalyst increase a reaction rate?

a)

by increasing the concentration of the reactants

b)

by increasing the number of collisions

c)

by lowering the activation energy

d)

by lowering the surface area

31.

What happens to the forward and reverse reactions when a system reaches its equilibrium state?

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32.

Decreasing the temperature of a system that has reached chemical equilibrium

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33.

Decide whether each of the following statements is true or false. Write True or False in the blank beside each statement.

a)

True

b)

False

34.

Boiling water is an example of a chemical change.

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35.

Substances produced as a result of a chemical reaction are called reactants.

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36.

When iron combines with sulfur to produce iron(II) sulfide, the balanced chemical equation is expressed as 2Fe + S⇒ 2FeS.

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37.

Synthesis reactions have a single product.

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38.

Gasoline burning in a car's engine is an example of an exothermic reaction.

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39.

Increasing the concentration of reactants will cause a chemical reaction to speed up.

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40.

Enzymes slow the rate of a reaction by reducing the effect of the catalysts.

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41.

Forces continue to act upon a system once it reaches equilibrium.

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42.

Why do scientists prefer chemical equations over word equations when describing chemical reactions?

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43.

Write the balanced chemical equation for the following word equation. Potassium chlorate (KClO3) decomposes to form potassium chloride and diatomic oxygen.

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44.

State the three parts of the collision model that must happen before reactants will react.

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45.

How does increasing the temperature affect reaction rates? Explain.

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46.

How do chemical equations model chemical reactions? Include the arrow symbol, coefficients, products, and reactants in your response.

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47.

Explain how 6Li + N₂ → 2Li3N represents a redox reaction. Which element goes through oxidation? Which element goes through reduction? How else could this reaction be classified?

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48.

Identify which portion of the graph represents the energy of the products, the energy of the reactants, and the activation energy. Does this graph show an exothermic or endothermic reaction? Explain.

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49.

Explain Le Châtelier's principle and then use it to predict how the reaction modeled by 4Al + 30₂ ⇒ 2Al₂O3 would be affected by (1) removing some aluminum(III) oxide from the system, (2) increasing the temperature, or (3) decreasing the pressure.

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