Practical: Preparation of soluble salts

What is the method to prepare soluble salts?

• Equipment: Bunsen burner, heatproof mat, beaker, glass rod, filter funnel, filter paper, evaporating basin, tripod, gauze, spatula.

• Step 1: Add excess copper(II) oxide powder to warm sulfuric acid in a beaker and stir to ensure the reaction occurs.

• Step 2: Continue heating gently until no more copper oxide reacts (excess solid remains).

• Step 3: Filter the mixture to remove excess solid, collecting the filtrate in an evaporating basin.

• Step 4: Heat the filtrate gently to concentrate the solution until crystals start to form on a glass rod.

• Step 5: Allow the solution to cool and crystallize.

• Step 6: Filter the crystals and leave them to dry in a warm place.

What type of reaction is used to prepare copper sulfate?

A neutralization reaction.

Why is an excess of copper oxide added to sulfuric acid?

To ensure all the acid reacts.

Why is the mixture filtered after the reaction?

To remove the excess copper oxide.

Why is the solution heated gently after filtration?

To concentrate the solution and allow crystals to form.

What happens when the solution is left to cool?

Crystals of copper sulfate form.

Why is it important to dry the crystals?

To remove water and ensure purity.

Write the word equation for the reaction between copper oxide and sulfuric acid.

Copper oxide + Sulfuric acid → Copper sulfate + Water

What safety precautions should you take during this practical?

Wear goggles and gloves, and handle acids with care.

Why should the acid not be heated to boiling?

To prevent splashing and ensure controlled reactions.

What is the color of copper sulfate crystals?

Blue

How can you ensure the crystals are pure?

By washing them with distilled water.

Why is copper(II) oxide used instead of copper metal?

Copper oxide reacts with acid, but copper metal does not.

What type of salt is copper sulfate?

A soluble salt.

Why is crystallization preferred over simple evaporation?

It ensures larger, purer crystals form.

What other metals or metal oxides could be used for similar reactions?

Zinc oxide, magnesium oxide, or iron oxide.