application aids

Question 1

Ca (s) used in process with V2O5

other than extracting vanadium, suggest one reason why this method is expensive?

Answer 1

• calcium produced by electrolysis
• uses large amount of energy
• calcium is very reactive / reacts with air and so needs to be extracted

Question 2

pure vanadium produced along with HCl gas through the reaction with VCl and H2

identify 2 hazards

why is pure vanadium produced

Answer 2

• hazards
  
  • HCl gas is toxic
  • explosion with hydrogen gas, it is flammible
• only other product easily removed because it is a gas

Question 3

Antimony can be extracted by reacting scrap iron with low-grade ores that contain antimony sulfide (Sb2S3).

3Fe + Sb₂S₃ 3FeS + 2Sb

Deduce one reason why the method of extraction of antimony from a low-grade ore, described in part (a), is a low-cost process. Do not include the cost of the ore.

Answer 3

• uses cheap waste iron
• single step process
  
  • uses less energy