Chapter 9 Review Guide

According to the law of conservation of mass, three atoms of calcium can react to produce six atoms of calcium

False

All chemical reactions occur at the same rate

False

Catalysts are always enzymes

False

Chemical equations are balanced by changing the subscripts of molecules

False

Exothermic reactions do not require any activation energy

False

When a substance combines with 0₂ and releases energy, a ______________ reaction has occurred.

Combustion

_________________ is a form of energy contained in chemical bonds

Chemical energy

A change in ____________ is a sign of energy being used in a chemical reaction A. Temperature B. Color C. Odor D. Texture

A.

Breaking a chemical bond _______________ A. Absorbs more energy from the surroundings B. Releases energy into the surroundings C. Creates energy that did not previously exist D. Uses up energy that then no longer exists

A.

If the arrangement of atoms in a substance changes, then which of the following is true? A. A chemical reaction has occurred B. The physical state of a substance changes C. The chemical properties of the substance stay the same but the physical properties change D. The physical properties of the substance stay the same but the chemical properties change.

A.

Sulfur trioxide reacts with water to make it sulfuric acid. This is a ___________ reaction. A. synthesis B. decomposition C. single-replacement D. Double replacement

A.

Which figure models a double-replacement reaction? A. I B. II C. III D. IV

A.

Which type of reaction requires more activation energy? A. Endothermic reactions B. Exothermic reactions C. They use the same amount of activation energy D. none of the above

A.

Why is the law of conservation of mass true? A. All atoms at the start of the chemical reaction are present at the end of the reaction B. All the molecules in a substance remain intact during a chemical reaction C. The substances at the start of a chemical reaction gather more atoms to make up for those lost in the reaction D. All the molecules at the start of the reaction are present at the end of the reaction

A.

Breaking a chemical bond _________ energy

Absorbs

The French chemist, ________________, conducted experiments that led to the law of conservation of mass

Antoine Lavoisier

Each substance written to the right of the arrow in a chemical equation is a _____________ A. Reactant B. Product C. Precipitate D. Catalyst

B.

Endothermic reactions ___________ A. Release more energy than they absorb B. Absorb more energy than they release C. Release and absorb exactly the same amount of energy D. Can either release more energy than they absorb or absorb more energy than they release, depending on the reaction

B.

Forming a chemical bond ___________ A. Absorbs more energy from the surroundings B. Releases energy into the surroundings C. Creates energy that did not previously exist D. Uses up energy that then no longer exists

B.

Metallic chlorates, when heated, results in metallic chlorides and oxygen. This is a __________ reaction. A. Synthesis B. Decomposition C. Single-replacement D. Double replacement

B.

Which figure models a synthesis reaction? A. I B. II C. III D. IV

B.

Which of the following is NOT a result of a chemical reaction? A. bubbles in boiling water B. A solid forming from two liquids reacting C. copper turning green when exposed to air D. The light given off by a firefly

B.

Which of the following is certain proof a chemical reaction has occurred? A. Bubbles B. change in chemical properties C. Change in color D. All of the above

B.

All substances _________ A. Are elements B. Are compounds C. Have a fixed number of atoms D. Contain hydrogen

C.

An exothermic reaction __________ A. absorbs thermal energy B. needs energy to be added constantly in order to continue C. releases thermal energy D. needs more energy to break the chemical bonds than it released when product form

C.

Some baking soda and vinegar were weighed separately and the weights added together. The two substances are mixed and a chemical reaction occurred, producing carbon dioxide, sodium acetate, and water. When the three new substances are weighed and the weights totaled, which of the following will be true? A. the original weights will be more because there was more mass B. The new weights will be more because there is more mass C. The two weights will be equal, because the mass is that same D. There is no way to know, because changes in mass are random

C.

Which figure models a decomposition reaction? A. I B. II C. III D. IV

C.

Which of the following materials will burn the fastest in open air? A. A log, two feet in diameter B. two logs, each one foot in diameter C. a pile of small splinters made from a two-foot diameter log D. Both logs and the splinters will burn at the same rate

C.

Zinc combines with hydrochloric acid, the zinc replaces hydrogen. The chemical equation for this reaction looks like: Zn+2HCI ; ZnCi₂+H₂. This is a _______ reaction. A. Synthesis B. Decomposition C. Single-replacement D. Double replacement

C.

A catalyst is which of the following? A. a reactant B. a product C. both a and b D. neither a nor b

D.

A(n) __________ slows or stops a chemical reaction. A. Catalyst B. Enzyme C. Activator D. Inhibitor

D.

According to the law of conservation of mass, how does the mass of the products in a chemical reaction compare to the mass of the reactants? A. There is no relationship B. The mass of the products is sometimes greater C. The mass of the reactant is greater D. The masses are always equal

D.

Atoms rearrange when _____________ A. Chemical bonds break B. Particles combine with enough energy C. neither a nor b D. both a and b

D.

Chemical reactions ______________. A. Release more energy than they absorb B. Absorb more energy than they release C. Release and absorb exactly the same amount of energy D. Can either release more energy than they absorb or absorb more energy than they release, depending on the reaction

D.

Sodium fluoride and silver nitrate become sodium nitrate and silver chloride. Carbonate and hydrogen ions become water and carbon dioxide. This is a _________ reaction. A. Synthesis B. Decomposition C. Single-replacement D. Double-replacement

D.

What has happened to the water in the illustration? A. The bonds between the water molecules have broken, and the water is turned into water vapor B. The water molecules spread out, and the water is turned into water vapor C. The bonds between the atoms of the water molecule have broken, and the water turned to water vapor D. The bonds between the atoms of the water molecule have broken, and instead of water, there is now hydrogen and oxygen

D.

Which figure models a single-replacement-reaction? A. I B. II C. III D. IV

D.

Which of the following changes is chemical rather than physical? A. Water is boiled B. Aluminum foil is crumpled C. Glass is shattered D. Wood is burned

D.

Which of the following factors would not speed up a chemical reaction? A. Increasing the concentration of a reactant B. adding a catalyst C. raising the temperature D. Making the reactant particles larger

D.

Hydrogen peroxide _________________ and forms water and oxygen gas.

Decomposes

Geoff observed an experiment in which one compound underwent a chemical reaction that produced two compounds. He classified this as a __________ reaction

Decomposition

Jaunita watched as two compounds reacted and changed into two different compounds. She determines the reaction that she observed was a _________ reaction

Double replacement

An explanation for the law of conservation of mass is that the same ______________ is present before and after the reaction

Number of atoms

Kalina conducted an experiment in which she started with one element and one compound and ended up with a different element and a different compound. She classified this as a ________________ reaction

Single replacement

If two or more substances combine to produce one substance, a __________ reaction has occurred

Synthesis

A chemical reaction in which more energy is absorbed than is released is endothermic

True

Activation energy is the minimum amount of energy needed for a chemical reaction to begin

True

Energy is needed to break the bonds in chemical reactions

True

When a chemical equation contains that same number of atoms on both sides, the equation is balanced

True

The ___________ switch places in a double-replacement reaction.

negative ions