North Carolina Science Grade 8

Chapter 13: Chemical Reactions

Chemical Reactions

1.
A(n) __________ is a substance that speeds up a chemical reaction without being permanently changed itself.
A)inhibitor
B)catalyst
C)endotherm
D)exotherm
2.
When iron combines with oxygen and water in the air to form rust, what substance in the reaction is the product?
A)water
B)oxygen
C)iron
D)rust
3.
Most chemical reactions __________ when temperature increases.
A)speed up
B)stop
C)continue at the same rate
D)slow down
4.
New substances produced by a chemical reaction are __________ .
A)products
B)reactants
C)coefficients
D)resultants
5.
The amount of substance present in a certain volume is called the __________ of that substance.
A)atomic number
B)concentration
C)activation energy
D)chemical formula
6.
The law of conservation of mass states that __________ .
A)matter can be created and destroyed but does not change forms
B)in a chemical reaction, efforts should be made to preserve rare elements without changing them
C)in a chemical reaction, the final mass of the products is always greater than the starting mass of the reactants
D)in a chemical reaction, matter is not created or destroyed, but is conserved
7.
The minimum amount of energy to start any chemical reaction is called the __________ of the reaction.
A)activation energy
B)energy requirement
C)energy of inhibition
D)energy of catalyzation
8.
__________ reactions absorb heat energy.
A)Catalyzed
B)Exothermic
C)Endothermic
D)Inhibited
9.
As a result of the experiments of Lavoisier, you know that in a chemical reaction, the mass of the products __________.
A)is less than the mass of the reactants
B)always equals the mass of the reactants
C)cannot be predicted based on the mass of the reactants
D)is twice as great as the mass of the reactants
10.
__________ is a way to describe a chemical reaction using chemical formulas and symbols.
A)The law of conservation of matter
B)Synthesis
C)A chemical equation
D)A physical law
11.
If electric current passes through water and initiates a reaction, what are the expected products?
A)hydrogen peroxide
B)hydrogen and oxygen
C)oxygen and water
D)hydrogen oxide
12.
In a chemical equation for an endothermic reaction, how is the energy requirement indicated?
A)A letter E appears in boldface type over the arrow.
B)The word energy is written as a reactant.
C)The word energy is written as a product.
D)A Greek letter, gamma, is drawn over the arrow.
13.
What does it mean for a chemical equation to be balanced?
A)There are the same number of atoms of each element on both sides of the equation.
B)The solid products weigh the same as the reactants.
C)The reactants and the products are written with the same coefficients.
D)The number of reactants is equal to the number of products.
14.
Which of the following statements about energy-releasing reactions is true?
A)The products are more stable.
B)The products are less stable.
C)The bonds of the products have more energy than those of the reactants.
D)The energy released is always in the form of heat.
15.
In chemical equations, __________ represent the number of units of each substance.
A)products
B)precipitates
C)reactants
D)numbers in front of the chemical formulas
16.
A change in which one or more substances are converted into new substances is a __________ .
A)physical change
B)chemical change
C)nuclear reaction
D)chemical fusion
17.
__________ tells you how much something changes during a period of time.
A)Speed
B)Age
C)A rate
D)A balanced chemical equation
18.
Which of the following statements about energy-absorbing reactions is true?
A)The bonds of the reactants have more energy than those of the products.
B)The reactants are less stable.
C)The energy supplied is always in the form of electricity.
D)The reactants are more stable.
19.
What type of substance slows down a chemical reaction?
A)catalyst
B)endotherm
C)inhibitor
D)enzymes
20.
__________ reactions release heat energy.
A)Exothermic
B)Catalyzed
C)Endothermic
D)Inhibited
Glencoe Online Learning CenterScience HomeProduct InfoSite MapContact Us

The McGraw-Hill CompaniesGlencoe

Please read our Terms of Use and Privacy Policy before you explore our Web site. To report a technical problem with this Web site, please contact the Web Producer.