Secondary 4

A pure sample of the insoluble salt barium carbonate can be made using the method given.

step 1 Dissolve barium chloride in water.

step 2 Separately dissolve sodium carbonate in water.

step 3 Mix the two solutions together.

step 4 Filter the mixture.

step 5

step 6 Dry the residue between two sheets of filter paper.

Which instruction is missing from step 5?

• Heat the residue to dryness.

• Heat the residue to the point of crystallisation.

• Place the filtrate in an evaporating basin.

• Wash the residue with water.

Substance X reacts with warm dilute hydrochloric acid to produce a gas which decolourises acidified aqueous potassium manganate(VII).

Substance X gives a yellow flame in a flame test.

What is X?

• potassium chloride

• potassium sulfite

• sodium chloride

• sodium sulfite

Which element is less reactive than the other members of its group in the Periodic Table?

• astatine

• caesium

• fluorine

• rubidium

The elements in Group IV of the Periodic Table are shown.

carbon

silicon

germanium

tin

lead

flerovium

What does not occur in Group IV as it is descended?

• The proton number of the elements increases.

• The elements become more metallic.

• The elements have more electrons in their outer shells.

• The elements have more electron shells.

Why are weather balloons sometimes filled with helium rather than hydrogen?

• Helium is found in air.

• Helium is less dense than hydrogen.

• Helium is more dense than hydrogen.

• Helium is unreactive.

Element E:

• forms an alloy

• has a basic oxide

• is below hydrogen in the reactivity series.

What is E?

• carbon

• copper

• sulfur

• zinc

Zinc metal is extracted from its ore zinc blende in a similar method to that used to extract iron from hematite.

In which way is zinc extraction different from iron extraction?

• Carbon and carbon monoxide are the main reducing agents.

• Hot air at the base of the furnace reacts with coke to keep the furnace hot.

• The metal is removed as a vapour at the top of the furnace.

• The metal oxide is added into the top of the furnace.

Stainless steel is an alloy of iron and other metals. It is strong and does not rust but it costs much more than normal steel.

What is not made from stainless steel?

• cutlery

• pipes in a chemical factory

• railway lines

• saucepans

The diagram shows some uses of water in the home.

For which uses is it important for the water to have been treated?

• 1 only

• 2 only

• 3 only

• 1,2 and 3

Oxides of nitrogen are found in polluted air.

Which statement about oxides of nitrogen is correct?

• Oxides of nitrogen are formed by the reaction of nitrogen with oxygen during the fractional distillation of liquid air.

• Oxides of nitrogen are formed in a car engine by the reaction of petrol with nitrogen from the air.

• Oxides of nitrogen are removed from exhaust gases by reaction with carbon dioxide in a catalytic converter.

• Oxides of nitrogen are removed from exhaust gases by reduction in a catalytic converter.