group 2 [I1] PAPER 1

Question 1

trend in solubility of group 2 metal sulfates?

Answer 1

decreases down the group

Question 2

trend in solubility of group 2 metal hydroxides?

Answer 2

increases down the group

Question 3

give the reaction between TiCl4 and Mg to extract titanium, state what type of reaction it is, and state and explain role of Mg in this reaction

Answer 3

• displacement reaction
• Mg is a reducing agent - Mg changes oxidation state from 0 to +2, so electrons are lost

Question 4

what is the charge on group 2 metal ions?

Answer 4

2+

Question 5

what is the trend in reactivity in group 2 and why?

Answer 5

• increases down the group
• more shielding
• larger atomic radius
• weaker electrostatic attraction between nucleus and outer electrons

Question 6

state and explain the trend in the first ionisation energies of the group 2 metals as you go down the group

Answer 6

• decreases
• more shielding / ion gets bigger
• weaker attraction between the nucleus and outer electron

Question 7

state the trend in the group 2 metals’ reactivity with water as you down the group

Answer 7

increases

Question 8

state and give a reason for the trend in atomic radius for atoms of the group 2 metals as you down the group

Answer 8

• increases
• more shielding

Question 9

give the equations for group 2 metals reacting with water and state the role of water in these reactions

Answer 9

water is an oxidising agent

• state symbols:
  - X = (s) 
  - H2O = (l) 
  - X(OH)2 = (aq) 
  - H2 = (g) 
[X = metal]

Question 10

equation and observations for the reaction of magnesium with steam

Answer 10

• white solid
• bright/white light
• Mg + H2O → MgO + H2

Question 11

uses of magnesium hydroxide

Answer 11

• in medicine as an antacid - neutralises stomach acid (since it is alkaline)
• in agriculture to neutralise acidic soil

Question 12

use of barium sulfate

Answer 12

• barium meals - allows x-rays of the digestive system
• as BaSO4 is insoluble, it isn’t absorbed into the bloodstream, so it isn’t harmful to ingest

Question 13

why is barium chloride solution used to test for sulfate ions, and why is it acidified?

Answer 13

• reacts to form barium sulfate, a white precipitate
• it is acidified to avoid a false positive result by removing any carbonate ions present as they also react with barium chloride to form a white precipitate

Question 14

the use of CaO and CaCO3 to remove SO2 from flue gases?

Answer 14

• CaO + 2H2O + SO2 → CaSO3 + 2H2O
• CaCO3 + SO2 → CaSO3 + CO2

Question 15

suggest two reasons why the reaction was faster at first with calcium and sulfuric acid than with magnesium and hydrochloric acid

Answer 15

• Ca is more reactive than Mg
• sulfuric acid has twice the H+ ion concentration
(H2SO4 vs. HCl → sulfuric acid has TWO H+, HCl only has one)

Question 16

why would the reaction of calcium with sulfuric acid stop, even though some calcium remained?

Answer 16

calcium sulfate is insoluble

Question 17

group 2 metals + sulfuric acid equation

Answer 17

[X = metal]

X + H2SO4 → XSO4 + H2

Question 18

why are different observations made when aqueous barium chloride is added separately to magnesium sulfate and magnesium nitrate

Answer 18

• BaSO4 and Ba(NO3)2 are formed
• barium sulfate is insoluble, but barium nitrate is soluble

Question 19

State what is observed when dilute aqueous sodium hydroxide is added to separate solutions of magnesium chloride and barium chloride.

Answer 19

• MgCl2 - slight white precipitate
• BaCl2 - colourless solution