Ch7 Chemical Reactions

Question 1

Physical change

Answer 1

Chemical composition remains constant

Question 2

Chemical change

Answer 2

The chemical composition changes; a chemical reaction occurs

Question 3

Evidence of chemical reactions (4)

Answer 3

1. a gas is produced
2. an insoluble solid is produced in a solution (deposition)
3. A permanent color change
4. Energy change

Question 4

If we add two aqueous solutions together we may observe the production of …

Answer 4

A solid substance/precipitate (ppt)

Question 5

A substance dissolves in water to give an …

Answer 5

Aqueous solution

Question 6

Exothermic reaction

Answer 6

Releases heat

Question 7

Endothermic reaction

Answer 7

Absorbs heat

Question 8

Chemical equation

Answer 8

describes a chemical reaction using formulas and symbols (A + B -> C + D)

Question 9

In the equation A + B -> C + D, A and B are …

Answer 9

Reactants

Question 10

In the equation A + B -> C + D, C and D are …

Answer 10

Products

Question 11

Where is the catalyst written in a chemical equation?

Answer 11

Above the arrow (speeds up the reaction without being consumed)

Question 12

What are two possible catalysts?

Answer 12

Heat and iron

Question 13

How is the catalyst heat symbolized?

Answer 13

change (triangle) over arrow

Question 14

NR

Answer 14

No Reaction

Question 15

Diatomic molecules

Answer 15

Composed of only two molecules bonded together

Question 16

How many nonmetals occur naturally as diatomic molecules? What are they?

Answer 16

7
H, N, O, and halogens F, Cl, Br, and I

Question 17

Balanced chemical equation

Answer 17

The number of atoms of each element is the same on both sides of the arrow

Question 18

Coefficient

Answer 18

Multiplies all subscripts in a chemical formula (3 H20 means 6H and 3O)

Question 19

What do you do if you get a fraction coefficient?

Answer 19

Multiply the whole equation by the denominator to get whole numbers

Question 20

The last step of balancing equations is…

Answer 20

Checking that you have the smallest whole number ratio of coefficients

Question 21

What five categories can chemical reactions be placed into?

Answer 21

1. Combination
2. Decomposition
3. Single-replacement
4. Double-replacement
5. Neutralization

Question 22

Combination/Cynthesis reactions

Answer 22

A reaction in which simpler substances are combined into a more complex compound

Question 23

Reactions of metals with oxygen

Answer 23

When metal is heated with oxygen gas, a metal oxide is produced (metal + oxygen gas -> metal oxide)

Question 24

Reactions of nonmetals w oxygen

Answer 24

nonmetal + oxygen gas -> nonmetal oxide

Question 25

Metal and nonmetal reactions

Answer 25

metal + nonmetal -> ionic compound

Question 26

When a main group metal reacts w a nonmetal, the formula is ... If the compound contains a transition metal, the formula is ...

Answer 26

Predictable, not predictable

Question 27

Decomposition reaction

Answer 27

A single compound is broken down into two or more simpler substances

Question 28

... is usually reuired to start a decomposition reaction

Answer 28

Heat

Question 29

Ionic compounds containing oxygen often decompose into ... and ...

Answer 29

a metal and oxygen gas

Question 30

What do metal /hydrogen/ carbonates decompose into? (3)

Answer 30

Metal carbonate, water, and carbon dioxide

Question 31

What do metal carbonates decompose into? (2)

Answer 31

Metal oxide and carbon dioxide gas

Question 32

Activity series

Answer 32

where a sequence of metals is arranged according to its ability to undergo a reaction

Question 33

The activity of a metal

Answer 33

A measure of its ability to compete in a replacement reaction

Question 34

The metal that displaces the other metal does so because ...

Answer 34

It is more active

Question 35

Where do metals that are most reactive appear in the activity series?

Answer 35

First

Question 36

Where do the least reactive metals appear in the activity series

Answer 36

Last

Question 37

Single-Replacement Reaction

Answer 37

A reaction where a more active metal displaces a less active metal in a compound

Question 38

Which metals react with acids?

Answer 38

The ones that precede H in the activity series

Question 39

Which metals do not react with acids

Answer 39

The ones that follow H in the activity series

Question 40

Magnesium Oxide chemical change

Answer 40

2Mg(s) + O2(g) -> 2MgO(s) One to One Ratio

Question 41

Active metals

Answer 41

Metals that can react directly with water (produce a hydroxide and hydrogen gas)

Question 42

Solubility rules

Answer 42

Used to predict in a compound will be soluble in water

Question 43

Double-Replacement Reaction

Answer 43

Two ionic compounds in aq solution switch anions and produce an insoluble substance AX + BZ -> AZ + BX

Question 44

AX + BZ -> AZ + BX If either of the products is an insoluble compound, then ...

Answer 44

A precipitate will appear (There's a chemical reaction)