Reactions

Question 1

Skeleton equation

Answer 1

a chemical equation that shows the reactants & products of a reaction but does not include the coefficients to balance the equation

Question 2

Balanced equation

Answer 2

an equation that has the same number of atoms on the reactants and products side

Question 3

Chemical formula

Answer 3

a chemical formula represents the elements in a compound and the ratio of atoms of each element (H2O)

Question 4

Chemical equation

Answer 4

represents a chemical reaction using symbols and formulas to show the reactants transforming into products

Question 5

Catalysts

Answer 5

a substance that increases the rate of a chemical reaction by lowering the activation energy required for the reaction to occur. they are not consumed in the reaction

Question 6

Bubble

Answer 6

a small pocket of gas that forms in a liquid often seen during a chemical reaction that produces gas

Question 7

Indicator

Answer 7

a substance that changes colour or properties in response to a change in conditions such as pH

Question 8

Boil

Answer 8

the process of heating a liquid to its boiling point, resulting in a phase change from liquid to gas

Question 8

Precipitate

Answer 8

a solid that forms as a result of a reaction, typically when two solutions react & produce an insoluable compound

Question 9

Insoluable

Answer 9

a substance that cannot dissolve in a solvent

Question 10

Endothermic

Answer 10

-the system absorbs energy from its surrondings
-the overall energy of the products is higher than that of the reactants
-if energy is being used it is a reactant

Question 11

Exothermic

Answer 11

-the system releases energy to its surrondings (transfers heat to its surrondings)
-the overall energy of the products is lower than that of the reactants

Question 12

Spontaneous energy

Answer 12

reactions that proceed immediately when two substances are mixed (no effort)
- can happen naturally under given conditions (temp/pressure)
- e.g., rusting of iron & melting of ice at room temp.

Question 13

Example of a catalyst

Answer 13

Manganese dioxide is a solid catalyst that accelerates the decomposition of hydrogen peroxide.
when it is added, it lowers the activation energy, meaning more hydrogen peroxide molecules can break down into water and oxygen gas at a faster rate

Question 14

Ways to tell a chemical reaction has occurred

Answer 14

Colour change
energy change (endothermic/exothermic)
gas formation
Irreversible
precipitate is formed

Question 15

Exothermic example

Answer 15

any reaction in which the product includes __ + E

Question 16

Endothermic example

Answer 16

any reaction in which the reactant include E + ___

Question 17

Synthesis reactions

Answer 17

occurs when two substances (elements) combine and form a compound

Question 18

Decomposition

Answer 18

occurs when a compound breaks up into elements or a few simpler compounds

Question 19

Combustion reactions

Answer 19

occurs when a hydrocarbon reacts with oxygen gas
- products are carbon dioxide and water

Question 20

What do you need in order to burn something

Answer 20

Fuel
oxygen
ignition

Question 21

Acid

Answer 21

nonmetallic oxide + water

Question 22

Nitrates

Answer 22

nitrite + oxygen

Question 23

Bicarbonates

Answer 23

carbonate + carbon dioxide + water

Question 24

Hydrates

Answer 24

salt + water

Question 25

Hydroxide

Answer 25

oxide + water

Question 26

Chlorates

Answer 26

chloride + oxygen

Question 27

To test for CO2

Answer 27

• reacts w/ limewater to form a precipitate of calcium carbonate

Question 28

To test for O2

Answer 28

light a wooden splint and blow it out
if oxygen is present, the splint will relight

Question 29

To test for H2

Answer 29

light a wooden splint
since hydrogen is explosive a pop sound will be produced

Question 30

Double displacement

Answer 30

reaction where two compounds exchange ions or elements to form to two new compounds

Question 31

Common characteristics of double displacement reactions

Answer 31

formation of parcipitate
formation of gas
formation of water

Question 32

Single displacement

Answer 32

reaction where one element displaces another element from a compound