Group 2 Metals

Question 1

Give one use for barium sulfate in medicine, and suggest why it is safe to use? [2]

Answer 1

barium meal (intestinal x-rays)            1 
it is insoluble, so not toxic                  1

Question 2

Magnesium hydroxide is used as an antacid to neutralise stomach acid.
Write an equation for the reaction that occurs? [1]

Suggest why magnesium hydroxide cannot be used as a base in titrations? [1]

Answer 2

Mg(OH)2 + HCl ———> MgCl2 + H2O 1

it is insoluble 1
will not react with the acid 1

Question 3

Magnesium can be used in the extraction of titanium from titanium (IV) chloride.
Write an equation for this reaction? [1]
State the role of the Mg in this reaction? [1]

Answer 3

TiCl4 + 2Mg ———-> Ti + 2MgCl2 1

Mg, acts as a reducing agent 1

Question 4

Magnesium is often used in fireworks as it produces a bright white flame when reacted with oxygen.

Suggest a reason why fireworks should not be put out using water and write an equation for the reaction? [3]

Answer 4

produces H2 1
risk of explosion 1

Mg + H2O ——–> MgO + H2 1

Question 5

Explain why a white ppt was formed when barium chloride reacted with copper (II) sulfate? [1]

Write a simple ionic equation for the reaction? [1]

Answer 5

BaSO4 is insoluble 1

Ba [2+] + SO4 [2-] ——–> BaSO4 1

Question 6

Explain why calcium has a higher melting point than that of strontium? [2]

Answer 6

smaller atomic radius 1

outer electrons are closer to the nucleus 1

Question 7

Describe and explain the trend in ionisation energy down Group 2? [3]

Answer 7

decreases 1
more electron shells, so more shielding 1
reduced attraction of electrons to nucleus 1

Question 8

When calcium reacts with water, it forms a metal hydroxide and hydrogen?
Write an equation for this reaction, and state the role of the water? [2]

Answer 8

Ca + H2O ———-> Ca(OH)2 + H2 1

H2O, acts as a oxidising agent

Question 9

Describe the trend in solubility of hydroxides and sulfate down Group 7? [2]

Answer 9

hydroxides =  increases               1  
sulfate = decreases          1

Question 10

Give two ways in which Group 2 metals are used in neutralisation of acids, and identity the hydroxides responsible for each use? [2]

Answer 10

Mg(OH)2 = antacid (neutralise stomach acid)         1 
Ca(OH)2 = neutralise acidic soils             1

Question 11

Calcium can be used in the removal of sulfur dioxide from flue gases, which causes acid rain

Write two equations to show the possible methods for the removal of SO2? [2]
Deduce the name of this process? [1]

Answer 11

CaO + 2H2O + SO2 ———> CaSO3 + 2H2O 1
CaCO3 + 2H2O + SO2 ——-> CaSO3 + 2H2O + CO2 1

wet scrubbing 1