Chemistry Past Questions and Answers

If the temperature of a gas is increased?

A The kinetic energy of the emolecules will decrease
B The pressure will decrease if the volume is constant
C The gas will occupy a greater volume if the pressure is constant
D The mass of the gas will decrease
E The pressure and volume will increase

Question 22:

When a little brine was added to a metal nitrate a white precipitate was formed which first turned violet and then black on exposure to ai. The metal nitrate is therefore?

A Sodium nitrate
B Mercuric nitrate
C Lithium nitrate
D Silver nitrate
E Potassium nitrate

Question 23:

If atom X with six electrons in its outermost shell combines with atom Y with one electron in its outermost shell to form an ionic compound, then?

A Six atoms of X will combine with one of Y
B Two atoms of X will combine with six of Y
C One atom of X will combine with two of Y
D Two atoms of X will combine with one of Y
E One atom of X will combine with six of Y

Question 24:

The nitrogen gas obtained by burning an excess of phosphorus in air has a density higher than the nitrogen from nitrogen compounds because the nitrogen from air is contaminated with?

A Some unburnt phosporus
B P₂O₅ vapour
C Some oxygen
D Rare gases
E Carbondioxide

Question 25:

When air is passed through alkaline pyrogallol and then over quicklime, the only gases left are?

A Nitrogen and carbondoxide
B The rare gases
C Nitrogen and oxygen
D Nitrogen and the rare gases
E Nitrogen, carbonioxide and the rare gases