C4,C5

Question 1

metal and acid reaction

Answer 1

• redox reaction
• metal + acid = a metal salt + hydrogen
• signs are: effervescence, squeaky pop, change in appearance
  e. g. iron + hydrochloric acid = iron chloride + hydrogen

Question 2

alkalis

Answer 2

• produce OH-(aq) ions when you add them to water

e. g. washing soda, oven cleaner soap, baking soda

Question 3

common acids

Answer 3

• HNO3: HydroNitric acid
• HCl: Hydrochloric acid
• H2SO4: Sulphuric acid

Question 4

bases

Answer 4

• substances that will neutralise acids

e. g. pure water

Question 5

ores

Answer 5

-rocks from which it is economical to extract the metals they contain

Question 6

pH scale

Answer 6

• pH less than 7 are acidic
• pH more than 7 are alkaline
• pH of 7 indicated a neutral solution

Question 7

why an acid is weak

Answer 7

• partly ionised
• 4-6 on ph scale
• orange/yellow colour

Question 8

Calculating limiting reactants

Answer 8

mass(g)/mr= moles of each reactant
Mg+2HCl=MgCl2+H2
4.8grams of Mg
7.3grams of 2HCl
4.8/24=0.2moles
7.3/36.5=0.2moles
-in balanced equation you can see that 1 mole of Mg will react with 2 moles of HCl
-so 0.2mol of mg will need 0.4mol of HCl to react completely
-we only have 0.2mol of HCl so hydrochloride acid is the limiting reactant

Question 9

reduction

Answer 9

gain of electrons

Question 10

calculating reacting masses

Answer 10

step 1: make sure equation is balanced
step 2: work out mole ratio
step 3: work out moles of known
step 4: use mole ratio to calculate moles of unknown
step 5: use moles and mr to calculate mass of unknown

Question 11

acid and alkalis reaction

Answer 11

• acid + alkali = a salt + water

e. g. hydrochloric acid + sodium hydroxide = sodium chloride + water

Question 12

acids

Answer 12

• produce H+(aq) ions when you add them to water

e. g. citric acid, sulfuric acid, ethan pic acid(orange juice, vinegar)

Question 13

why an acid is strong

Answer 13

• fully ionised
• 0-2 on ph scale
• red colour

Question 14

concentration of H+ ions ph value

Answer 14

0.10=1.0
0.010=2.0
0.0010=3.0
etc

Question 15

acid and base reaction

Answer 15

• neutralisation reaction occurs
• acid + base = a metal salt + water
  e. g. hydrochloric acid + iron oxide = iron chloride + water

Question 16

Displacement reactions

Answer 16

-a more reactive metal will displace a less reactive metal from its aqueous solution

Question 17

common alkalis

Answer 17

• NaOH: Sodium hydroxide
• KOH: Potassium hydroxide
• Ca(OH)2: Calcium hydroxide

Question 18

number of moles equation

Answer 18

mass(g)/Ar=Number of Moles
Or
mass(g)/Mr=number of moles

Question 19

acids and carbonate reaction

Answer 19

acid + a carbonate = a salt + water + carbon dioxide

e.g. hydrochloric acid + calcium carbonate = calcium chloride + water + carbon dioxide

Question 20

oxidation

Answer 20

loss of electrons