Quiz about Chemical Reactions

Question 1

In an endothermic reaction, heat is ...

Accepted Answer

taken in or absorbed

Answer

given out or released

Question 2

Baking bread and cooking an egg are examples of....?

Accepted Answer

Endothermic processes

Answer

Exothermic processess

Answer

None of these

Question 3

Exothermic reactions...

Accepted Answer

Release energy

Answer

Absorb energy

Answer

Release Color

Answer

Absorb Color

Question 4

When does a chemical reaction stop?

Accepted Answer

When the limiting reactant is used up

Answer

When the lab is finished

Answer

When the excess reactant is used up

Answer

Chemical reactions never stop

Question 5

What is essential for a combustion reaction to begin?

Accepted Answer

Fuel, oxygen and heat

Answer

Carbon dioxide

Answer

Fuel

Answer

Water and oxygen

Question 6

Which of the following shows the correct way to balance the chemical equation?
Fe + O₂ -> Fe₂O₃

Accepted Answer

4Fe + 3O₂ -> 2Fe₂O₃

Answer

2 Fe + 3O₂ -> Fe₂O₆

Answer

4 Fe + O₆ -> 2Fe₂O₃

Answer

None of the options are correctly balanced.

Question 7

Balance this equation...
HgO --> Hg + O₂

Accepted Answer

2HgO --> 2Hg + O₂

Answer

It is balanced

Answer

2HgO --> Hg + O₂

Answer

I don't know...Oh well!

Question 8

Ice melting

Accepted Answer

Physical Change

Answer

Chemical Change

Question 9

What happens in ALL chemical changes?

Accepted Answer

A new substance is formed

Answer

Change in state of matter

Answer

Bubbles are produced

Answer

An explosion

Question 10

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

Accepted Answer

balanced

Answer

unbalanced

Question 11

In reactions, products must be equal to..

Accepted Answer

Reactants

Answer

Products

Answer

Starters

Answer

Enders

Question 12

According to the law of conservation of mass, how does the amount of each element on the product side compare to each element on the reactant side?

Accepted Answer

The amount of atoms on each side is equal

Answer

The amount of atoms on the product side is greater

Answer

The amount of atoms on the reactant side is greater

Answer

Depends on the reaction

Question 13

Which reaction type is the following:

C₅H₁₀ + O₂ --> CO₂ + H₂O

Accepted Answer

Complete Combustion

Answer

Decomposition

Answer

Synthesis

Answer

Double Replacement

Question 14

In chemical reactions, what does the principle of conservation of mass mean?

Accepted Answer

Matter is not created or destroyed.

Answer

The total mass of the reactants is greater than the total mass of the products.

Answer

The total mass of the reactants is less than the total mass of the products.

Answer

Matter is not changed.

Question 15

The process by which one or more substances change to produce one or more different substances

Accepted Answer

Chemical Reaction

Answer

Chemical Process

Answer

Reactant

Question 16

Which observation(s) might be used as evidence that a chemical reaction occurred?

Accepted Answer

All of the above

Answer

Color change

Answer

Odor change

Answer

Properties change

Question 17

Which is an example of a physical change?

Accepted Answer

Freezing water

Answer

Burning wood

Answer

Rust on a car

Answer

Cooking food

Question 18

When a scientist mixed two chemicals, an exothermic reaction takes place. Which of the following would be proof that the reaction was exothermic?

Accepted Answer

a temperature increase

Answer

a change of color

Answer

a change of state

Answer

a temperature decrease

Question 19

In the reaction methane + oxygen turns into carbon dioxide + water, the methane and oxygen are called _______________.

Accepted Answer

reactants

Answer

products

Answer

neutrals

Answer

energizers

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