Quiz about Chemical Reactions Quiz

Question 1

What are the chemicals called that we have at the start of a chemical reaction?

Accepted Answer

Reactants

Answer

Products

Answer

Catalysts

Answer

Enzymes

Question 2

What happens to the atoms in substances when a chemical reaction takes place?

Accepted Answer

They are rearranged to form new chemicals

Answer

They disappear

Answer

They remain unchanged

Answer

They become inert

Question 3

What are the substances formed in a chemical reaction called?

Accepted Answer

Products

Answer

Reactants

Answer

Catalysts

Answer

Enzymes

Question 4

Which of the following is an evidence of a chemical reaction?

Accepted Answer

Color change

Answer

Change in shape

Answer

Melting

Answer

Freezing

Question 5

What is an example of a chemical reaction that involves the formation of a gas?

Accepted Answer

Baking soda added to vinegar

Answer

Melting ice

Answer

Dissolving sugar in water

Answer

Cutting paper

Question 6

Which of the following is NOT an evidence of a chemical reaction?

Accepted Answer

Change in size

Answer

Formation of a precipitate

Answer

Formation of a gas

Answer

Change in odor

Question 7

What is an example of a chemical reaction that involves a change in odor?

Accepted Answer

Eggs rotting

Answer

Bread dough baking

Answer

Ice melting

Answer

Water boiling

Question 8

Which of the following is an example of a chemical reaction that involves a change in light or temperature?

Accepted Answer

Fireworks

Answer

Ice melting

Answer

Water freezing

Answer

Cutting wood

Question 9

What is a chemical equation?

Accepted Answer

A) A written representation of chemical reactions that take place

Answer

B) A graphical representation of chemical reactions

Answer

C) A verbal description of chemical reactions

Answer

D) A physical model of chemical reactions

Question 10

What do chemical equations use to show reactants and products?

Accepted Answer

B) Symbols and formulas

Answer

A) Colors and shapes

Answer

C) Numbers and letters

Answer

D) Pictures and diagrams

Question 11

In a chemical equation, what do the reactants represent?

Accepted Answer

B) The start of the reaction

Answer

A) The end of the reaction

Answer

C) The middle of the reaction

Answer

D) The by-products of the reaction

Question 12

In a chemical equation, what do the products represent?

Accepted Answer

C) The end of the reaction

Answer

A) The start of the reaction

Answer

B) The middle of the reaction

Answer

D) The by-products of the reaction

Question 13

What does the law of conservation of mass state about chemical reactions?

Accepted Answer

Mass is neither lost nor gained during chemical reactions.

Answer

Mass is lost during chemical reactions.

Answer

Mass is gained during chemical reactions.

Answer

Mass is only lost during exothermic reactions.

Question 14

According to the law of conservation of mass, the mass of the reactants is equal to:

Accepted Answer

The mass of the products.

Answer

Half the mass of the products.

Answer

Twice the mass of the products.

Answer

The mass of the products minus the mass of the reactants.

Question 15

What can be used to replace chemical formulas to describe each reaction?

Accepted Answer

Words

Answer

Numbers

Answer

Symbols

Answer

Equations

Question 16

Which of the following is NOT a type of chemical reaction we studied?

Accepted Answer

Neutralization

Answer

Synthesis

Answer

Decomposition

Answer

Single-replacement

Question 17

Which type of reaction involves the combination of two or more substances to form a single product?

Accepted Answer

Synthesis

Answer

Decomposition

Answer

Single-replacement

Answer

Combustion

Question 18

In which type of reaction does a single compound break down into two or more simpler substances?

Accepted Answer

Decomposition

Answer

Double-replacement

Answer

Combustion

Answer

Synthesis

Question 19

Which type of reaction involves an element replacing another element in a compound?

Accepted Answer

Single-replacement

Answer

Double-replacement

Answer

Combustion

Answer

Synthesis

Question 20

Which type of reaction involves the exchange of ions between two compounds to form new compounds?

Accepted Answer

Double-replacement

Answer

Synthesis

Answer

Decomposition

Answer

Single-replacement

Question 21

Which type of reaction typically involves a substance reacting with oxygen to produce heat and light?

Accepted Answer

Combustion

Answer

Decomposition

Answer

Synthesis

Answer

Double-replacement

Question 22

What happens during a decomposition reaction?

Accepted Answer

A compound breaks into two or more simpler substances

Answer

A compound combines with another compound

Answer

A compound changes its state of matter

Answer

A compound remains unchanged

Question 23

In the given diagram, what are the products of the decomposition reaction?

Accepted Answer

Nitrogen (N2) and Hydrogen (H2)

Answer

Oxygen (O2) and Water (H2O)

Answer

Carbon dioxide (CO2) and Water (H2O)

Answer

Sodium (Na) and Chlorine (Cl2)

Question 24

What is a single replacement reaction?

Accepted Answer

One element replaces a similar element in a compound.

Answer

Two elements combine to form a compound.

Answer

A compound breaks down into two or more elements.

Answer

Two compounds react to form two new compounds.

Question 25

What is a double replacement reaction?

Accepted Answer

A reaction where the positive and negative ions of ionic compounds switch places to form two new compounds.

Answer

A reaction where two elements combine to form a compound.

Answer

A reaction where a compound breaks down into two or more simpler substances.

Answer

A reaction where a single element replaces another element in a compound.

Question 26

Why do we balance chemical equations?

Accepted Answer

To show the law of conservation of mass.

Answer

To create new elements.

Answer

To increase the number of atoms.

Answer

To change the properties of reactants.

Question 27

What must be true about the atoms in the reactants and products in a balanced chemical equation?

Accepted Answer

The atoms in the reactants must equal the atoms in the products.

Answer

The atoms in the reactants must be fewer than the atoms in the products.

Answer

The atoms in the reactants must be more than the atoms in the products.

Answer

The atoms in the reactants must be different from the atoms in the products.

Question 28

What do subscripts in a chemical formula indicate?

Accepted Answer

The number of atoms of each element

Answer

The type of chemical bond

Answer

The state of matter

Answer

The temperature at which the compound is stable

Question 29

If a chemical formula has no subscript next to an element, how many atoms of that element are present?

Accepted Answer

1

Answer

0

Answer

2

Answer

3

Question 30

What does the coefficient in a chemical formula indicate?

Accepted Answer

The number of molecules of the compound

Answer

The type of elements in the compound

Answer

The number of atoms of each element

Answer

The mass of the compound

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