Chemical Changes

What are the products of the reaction of zinc with hydrochloric acid?

• Zinc hydrochloride and hydrogen

• Zinc chloride and water

• Zinc hydrochloride and hydrogen

• Zinc chloride and hydrogen

Which substance is oxidised in the reaction represented by the ionic equation below?

Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s)

• Zinc because it loses electrons

• Copper because it gains electrons

• Zinc because it gains electrons

• Copper because it loses electrons

If a solution has a pH of 8, it is ______. Some vinegar has a pH of 4, so the vinegar is acidic.

In the electrolysis of molten lead bromide, the substance produced at the cathode is ______.

Sulfuric acid is a strong acid. What is meant by a strong acid?

Aluminium is extracted from aluminium oxide by electrolysis.

In the electrolysis cell, there is a mixture of aluminium oxide and molten cryolite. Explain why.

Draw a neat diagram of electrolytic cell used in the purification of copper and label the following: a) Anode b) Cathode

The electrolysis of copper sulfate solution makes two products, one at each electrode.

Draw one line from each electrode to the product produced there.

Describe how aluminium is obtained from aluminium oxide on a large scale.

In your answer, refer to the apparatus shown in Figure 1.

Explain why the anode must be replaced regularly.

A student places 25 cm³ of a solution of sodium hydroxide, NaOH, in a flask.

The concentration of sodium hydroxide is 0.5 mol/dm³.

What is the amount in moles of sodium hydroxide in the flask

• 12.5

• 1.25

• 0.125

• 0.0125