#2.Which method is most suitable for obtaining a pure, dry sample of sodium chloride, from a mixture of solid sodim chloride and sand?

Heat the mixture gently and collect the substance which boils off.

Heat the mixture gently and collect the substance which melts.

Shake the mixture with water and distill off the liquid.

Shake the mixture with water, filter and evaporate the filtrate.

#3.Which statement is correct for all neutral atoms?

number of electrons=number of protons+number of neutrons

number of neutrons=number of protons+number of electrons

number of protons=number of electrons

number of protons=number of neutrons

#4. What would be the best way of slowing down the reaction between magnesium and hydrochloric acid?

add catalyst to the reactants

dilute the acid used in the reaction

stir the reagents

use magnesium powder instead of ribbon

#5. Which of the following oxides reacts both with with dilute hydrochloric acid and aqueous sodium hydroxide?

aluminium oxide

calcium oxide

copper (II) oxide

iron (III) oxide