chemical reactions

Question 1

what is oxidation

Answer 1

when the metal gains oxygen or the loss of electrons

Question 2

what is reduction

Answer 2

when a compound loses it oxygen or the gain of electrons

Question 3

what happens when a metal reacts with water

Answer 3

it gives off the salt being the metal hydroxide and hydrogen

Question 4

what does the reactivity of a metal depend on

Answer 4

it depends on how easily they lose an electron. This could be due to different factors such as inter molecular forces of attraction or amount of electrons in outermost shell

Question 5

when will a metal be displaced from its compound

Answer 5

when it is reacted with a more reactive element ( a more reactive element will displace a less reactive element )

Question 6

what is an aqueous solution

Answer 6

aqueous mean dissolved in water

Question 7

what is an acid

Answer 7

an acid ionizes in an aqueous solution to form hydrogen ions

Question 8

what is a base

Answer 8

a base is a chemical that can neutralise an acid producing a salt and water and are usually metal oxides or metal hydroxides

Question 9

what is an alkali

Answer 9

a base the is soluble in water
an alkali ionizes to produces OH- ions in an aqueous solution

Question 10

what is a neutralization reaction

Answer 10

when the h+ ions react with OH- ions to form water
and a neutral
acid + alkali –> salt + water

Question 11

what are the 3 main acids in chemistry

Answer 11

HCl hydrochloric acid
H2SO4 sulfuric acid
HNO3 nitric acid
all acids contain hydrogen

Question 12

what happens when an acid reacts with a metal

Answer 12

acid + metal –> salt + hydrogen

Question 13

what ions do salts contain

Answer 13

the negative ion comes from the acid and the positive ion comes from the base or alkali

Question 14

what happens when an acid reacts with a metal carbonate

Answer 14

it produces a salt water and carbon dioxide

Question 15

what happens when an acid reacts with a metal carbonate

Answer 15

it produces a salt water and carbon dioxide

Question 16

why can we not react copper with sulfuric acid to form copper sulphate

Answer 16

copper is too unreactive

Question 17

how would you conduct a practical to make copper sulfate crystals

Answer 17

add a fixed volume off sulfuric acid to be the limiting reactant then heat the acid to nearly boiling so it doesn’t bubble over. slowly add in copper oxide until some is left visible at the bottom then filter unreacted copper oxide then conduct crystallization

Question 18

what is a strong acid

Answer 18

they fully ionize to from H+ ions for example hydrochloric acid, sulfuric acid, nitric acid

Question 19

what is a weak acid

Answer 19

a weak acid does not fully ionize to form H+ ions as it is a reversible reaction for example carbonic acid, ethanoic acid, citric acid

Question 20

what is a weak acid

Answer 20

a weak acid does not fully ionize to form H+ ions as it is a reversible reaction for example carbonic acid, ethanoic acid, citric acid

Question 21

as the pH goes down by one what happens to the concentration of H+ ions

Answer 21

they increase by 10x or one order of magnitude

Question 22

what do we call the natural curve that a liquid has

Answer 22

the meniscus

Question 23

what is the formula for number of moles regarding concentration and volume

Answer 23

number of moles = concentration (mol/dm³) * volume (dm³)

Question 24

how do you get from mol/dm³ to g/dm³

Answer 24

multiply by the relative formula mass

Question 25

how do you get from mol/dm³ to g/dm³

Answer 25

multiply by the relative formula mass

Question 26

why does the electrolyte in electrolysis have to be molten or dissolved in water

Answer 26

because in solids ions are not free to move

Question 27

what are the electrodes made of

Answer 27

usually graphite as it can conduct electricity

Question 28

what happens at the negative electrode

Answer 28

the metal is attracted to the negative electrode and gains electrons which is an example of a reduction reaction

Question 29

what happens at the negative electrode

Answer 29

the non metal is attracted to the negative electrode and loses electrons which is an example of a reduction reaction. group 7 elements will for diatomic particles so the half equation will look different

Question 30

why is aluminium oxide mixed with a cryolite

Answer 30

a cryolite is substance that reduces the boiling point of the aluminum so electrolysis will require less energy

Question 31

why should the anode be regularly replaced

Answer 31

the oxygen car react with the graphite (made of carbon) to form carbon dioxide

Question 32

why is electrolysis expensive

Answer 32

because melting the compound requires a lot of energy and a lot of energy is needed to produce the electric current

Question 33

what do water molecules ionize into

Answer 33

the split into H+ ions and OH- ions

Question 34

what happens at the cathode in a aqueous solution

Answer 34

if the metal is more reactive than hydrogen then hydrogen forms instead of the metal

Question 35

what does inert mean

Answer 35

unreactive

Question 36

what is the half equation for the reaction at the anode in an aqueous solution

Answer 36

4OH- = O2 + 2H2O = 4e-

Question 37

what is the exception to oxygen being produced at the anode in an aqueous solution

Answer 37

if the gas is a halide ion it will be produced instead of the oxygen