topic 5 ~ chemical changes

Question 1

what is a displacement reaction?

Answer 1

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

Question 2

what is oxidation?

Answer 2

> chemicals are oxidised if they gain oxygen in a reaction

>chemicals are oxidised if they lose electrons in a reaction

Question 3

what is reduction?

Answer 3

> chemicals are reduced if they lose oxygen in a reaction

>chemicals are reduced if they gain electrons in a reaction

Question 4

what is an acid?

Answer 4

a chemical that dissolves in water to produce H+ ions. acids are proton donors

Question 5

what is a base?

Answer 5

a chemical that reacts with acids and neutralises them

Question 6

what is an alkali?

Answer 6

a soluble base that produces OH- ions in solution

Question 7

what is the difference between bases and alkalis?

Answer 7

all alkalis are bases but not all bases are alkalis, like how all Dalmatians are dogs but not all dogs are Dalmatians. an alkali is a kind of base

Question 8

what is neutralisation?

Answer 8

when a neutral solution is formed from reacting an acid and an alkali

Question 9

what is pH?

Answer 9

a scale to measure acidity/acidity. a decrease of 1 pH unit causes a 10x increase in concentration of H+ ions

Question 10

what is a strong acid?

Answer 10

an acid that completely ionises in solution

Question 11

what is a weak acid?

Answer 11

an acid that only partially ionises in solution