A procedure for preparing copper(II) sulfate crystals is illustrated: (1) Put dilute sulfuric acid into a beaker. (2) Heat the acid gently. (3) Add copper(II) oxide until some remains unreacted. (4) Filter the mixture. (5) Evaporate the filtrate until crystals begin to appear. (6) Allow the filtrate to cool. What are the purposes of step 3 and step 4?
- Astep 3: to ensure all of the acid has reacted; step 4: to obtain solid copper(II) sulfate
- Bstep 3: to ensure all of the acid has reacted; step 4: to remove the excess of copper(II) oxide
- Cstep 3: to speed up the reaction; step 4: to obtain solid copper(II) sulfate
- Dstep 3: to speed up the reaction; step 4: to remove the excess of copper(II) oxide