Chemistry: Chemical Changes

Question 1

what pH is an acid

Answer 1

0 - 6

Question 2

what pH is a base

Answer 2

8 - 14

Question 3

what pH is neutral

Answer 3

7

Question 4

what is an alkaline

Answer 4

base that dissolves in water

Question 5

what is the reaction between acids and bases called

Answer 5

neutralisation

Question 6

what are titrations used for

Answer 6

find out concentrations

Question 7

what do strong acids do in water

Answer 7

ionise completely in water and all acids particles dissociate to release H+ ions

Question 8

what do weak acids do in water

Answer 8

do not fully ionise and only a small proportion of acid particles dissociate to release H+ ions

Question 9

name the reactivity series in order of reactivity

Answer 9

Potassium K, Sodium Na, Lithium Li, Calcium Ca, Magnesium Mg, Carbon C, Zinc Zn, Iron Fe, Hydrogen H, Copper Cu

Question 10

what is an oxidation reaction

Answer 10

gain of oxygen

Question 11

what is a reduction reaction

Answer 11

loss of oxygen

Question 12

what is a displacement reaction

Answer 12

more reactive metal will displace a less reactive metal from its compound

Question 13

what is electrolysis

Answer 13

using electrical current to split up a compound into ions

Question 14

where do positive ions in the electrolyte go

Answer 14

move towards the cathode (negative electrode) and gain electrons

Question 15

where do negative ions in the electrolyte go

Answer 15

move towards the anode (positive electrode) and lose electrons

Question 16

why are some solids made into molten for electrolysis

Answer 16

an ionic solid can’t be electrolysed because the ions are in fixed positions and can’t move

Question 17

what are the two rules for what is collected at the electrodes during electrolysis in an aqueous solution

Answer 17

at the anode either OH- ions or a halide ion

at the cathode either H+ ions or a less reactive positive ion