Chemical Reactions + Bonding

Question 1

what does a chemical formula look like?

Answer 1

reactants > products

Question 2

a balanced chemical equation

Answer 2

when you balance the amount of atoms on each side

Question 3

law of conservation of mass

Answer 3

during a chemical reaction atoms cannot be created or destroyed

Question 4

when molecules store energy what is it called

Answer 4

chemical potential energy

Question 5

how do molecules release energy

Answer 5

when they react with each other they release energy

Question 6

exothermic

Answer 6

when the amount of energy in the reactants is greater than the products it will be released in the form of heat

Question 7

endothermic

Answer 7

when the amount of energy in the reactants is less than the amount in the products and releases as cold

Question 8

different types of reactions

Answer 8

combustion
combination
neutralisation
displacement
decomposition
precipitate

Question 9

combustion

Answer 9

produces light and heat, oxygen is present

fuel + oxygen > carbon dioxide and water

Question 10

what happens if oxygen is limited in a combustion reaction (incomplete combustion)

Answer 10

it has two reactions;
fuel + limited oxygen > carbon monoxide + water
fuel + limited oxygen > carbon + water

Question 11

what are the normal fuels?

Answer 11

hydrocarbons

Question 12

combination

Answer 12

occur when two reactants come together to form one product

x + y > xy

Question 13

neutralisation

Answer 13

when an acid reacts with a base

acid + base > salt + water

Question 14

displacement

Answer 14

when the reactants are rearranged to form a different product
xy + z > x + yz

Question 15

decomposition

Answer 15

when a single reactant breaks down into 2

xy > x + y

Question 16

precipitate

Answer 16

when 2 clear solutions are mixed together to form an insoluble solid
wx(aq) + yz(aq) > wy(s) + xz(aq)
form of displacement

Question 17

respiration chemical equation

Answer 17

glucose + oxygen gas > carbon dioxide + water

c6h12o6 + 6o2 > 6co2 + 6h2o

Question 18

corrosion

Answer 18

metals combining with oxygen to form rust

metal + oxygen > metal oxide

Question 19

thermal decomposition

Answer 19

substances that decompose when heated

Question 20

diatomic

Answer 20

only exists as 2

Question 21

soluable

Answer 21

can dissolve in water
ANSPAM
(aq)

Question 22

insoluable

Answer 22

doesnt dissolve in water
form a solid precipitate
(s)

Question 23

ANSPAM

Answer 23

all nitrates, sodium, potassium and ammonium are always soluble

Question 24

states

Answer 24

(aq) - solution in which water is the solvent
(l) - water
(s) - anything solid
(g) - anything in a gas state

Question 25

ions

Answer 25

are atoms that have become charged because they have gained or lost electrons

Question 26

cations

Answer 26

have more protons than electrons

Question 27

anions

Answer 27

have more electrons than protons

Question 28

what controls the rate of the reaction

Answer 28

temperature
concentration
agitation
surface area of reactants
catalysts
enzymes

Question 29

temperature

Answer 29

increasing temp increase rate of reaction

decreasing temp lowers rate of reaction

Question 30

concentration

Answer 30

the amount of substance present in a liquid or gas
increasing the amount raises the reaction rate
decreasing the amount decreases the reaction rate

Question 31

agitation

Answer 31

stirring the reactants

ensures the reactants are kept in contact

Question 32

surface area of reactants

Answer 32

when a solid is crushed to expose more surface area

Question 33

catalysts

Answer 33

are chemicals that speed up the reactions but are not used up in the reaction
‘chemical helpers’
reduce the amount of energy required to convert reactants to products
make it easier for reactant molecules to combine and form products

Question 34

enzymes

Answer 34

are biological catalysts

hold reactant molecules together to form products

Question 35

ionic compound

Answer 35

a substance made up of positive and negative ions