Group 2

Question 1

describe the trend in solubility of group 2 metal hydroxides down the group (1)

Answer 1

solubility of metal hydroxides increases

Question 2

what is the pH of Mg(OH)2

Answer 2

pH 10

Question 3

what uses does mg(OH)2 have ?

Answer 3

neutralise stomach acid

Question 4

what is the pH of Ca(OH)2

Answer 4

11

Question 5

what uses does Ca(OH)2 have ?

Answer 5

neutralise acidic soil in agriculture

Question 6

other than Mg(OH)2 what else can be used to neutralise stomach acid ?

Answer 6

CaCO3

Question 7

describe the trend in pH of group 2 metal hydroxides down the group (1)

Answer 7

pH of metal hydroxides increases down the group (becomes more alkaline)

Question 8

describe the trend in solubility for group 2 metal carbonates down the group (1)

Answer 8

solubility of metal carbonates decreases

Question 9

state the solubility of each group 2 metal carbonate

Answer 9

BeCO3 - barely soluble
MgCO3 - barely soluble
CaCO3 - insoluble
SrCO3 - insoluble
BaCO3- insoluble

Question 11

describe the trend in the solubility of group 2 metal sulfates (1)

Answer 11

solubility of metal sulfates decreases

Question 12

state the solubility of each group 2 metal sulfate

Answer 12

BeSO4 - soluble
MgSO4 - soluble
CaSO4 - insoluble
SrSO4 - insoluble
BaSO4 - insoluble

Question 13

describe the trend in reactivity down group 2 (6)

Answer 13

• reactivity increases down group
• greater number of electron shells
• atomic radius increases
• greater electron shielding
• weaker nuclear attraction between nucleus and outermost electron
• form cations (lose electrons) more readily

Question 14

which group 2 elements will be better reducing agents ? (1)

Answer 14

those further down the group (form cations more readily (lose e-))

Question 15

write a balanced symbol equation for the reaction between calcium (any group 2 metal) and oxygen

Answer 15

2Ca(s) + O2(g) = 2CO (s)

Question 16

describe how beryllium reacts with water (1)

Answer 16

no reaction with water

Question 17

describe how magnesium reacts with water (2)

Answer 17

• very slow reaction with water
• reacts vigorously with steam (H2O (g)) but produces Magnesium oxide

Question 18

write the equation for the reaction of any group 2 metal (not beryllium or magnesium) reacting with water

Answer 18

Ca(s) + 2H2O(l) = Ca(OH)2 (s) + H2(g)

Question 19

what observations can be made when a group 2 metal reacts with water (2)

Answer 19

• effervescence
• alkaline solution formed (OH-)

Question 20

describe the differences in chemistry and observations between the reactions o f magnesium with water and steam (8)

Answer 20

1. with water :
   - very slow reaction
   - slight effervescence produced
   - magnesium hydroxide produced
   - alkaline solution pH around 10
2. with steam
   - fast reaction
   - faster effervescence produced
   - magnesium oxide produced
   - no alkaline solution

Question 21

write the equation for the reaction of any group 2 metal with any dilute acid eg. HCl

Answer 21

Ca(s) + 2HCl(aq) = CaCl2 (aq) + H2(g)

Question 22

which reaction can group 2 metal carbonates undergo ? (1)

Answer 22

thermal decomposition

Question 23

what is a thermal decomposition reaction ?

Answer 23

• breakdown compound into 2 or more diff substances using heat

Question 24

what will affect the amount of heat energy needed for a group 2 metal carbonate to undergo thermal decomposition ? (1)

Answer 24

• charge density

Question 25

explain how charge density will affect the amount of heat energy needed for a group 2 metal carbonate to undergo thermal decomposition ? (2)

Answer 25

• greater charge density of metal ion = more polarised carbonate ion becomes
• greater polarisation = less heat needed to break C-O bond

Question 26

describe the trend in charge density down of group 2 metal carbonates down the group (2)

Answer 26

• charge density decreases
• thermal stability increases (more heat needed)

Question 27

what is a combination reaction ? (1)

Answer 27

when 2 or more compounds or elements combine to form 1