Question bank: Unit 1 — Chemical Reactions and Their Environmental Impacts

2Mg + O₂ → 2MgO is an example of a:

When red mercury(II) oxide is heated, the gas released is:

The product of burning steel wool in air is mainly:

Which metal forms a black layer of oxide on its surface when heated in a Bunsen flame without burning with a visible flame?

A reaction in which one compound breaks down into two or more simpler substances is called:

Heating calcium carbonate gives:

Which element is NOT able to displace hydrogen from dilute hydrochloric acid?

Which list shows the metals in descending order of reactivity?

The gas produced when zinc reacts with dilute hydrochloric acid burns with a "pop" sound. It is:

Aluminium reacts slowly at first with dilute hydrochloric acid because:

Sodium is stored under kerosene because it:

In 2Na + 2H₂O → 2NaOH + H₂, the solution formed turns red litmus:

Magnesium needs hot water to react while sodium reacts with cold water. This shows that:

When a zinc rod is placed in copper sulphate solution, the blue colour fades because:

Which reaction would NOT occur?

Aluminium foil cleans tarnished silver because aluminium:

Which colour does universal indicator show at the neutralisation point?

NaOH + HCl → NaCl + H₂O is a:

When dilute hydrochloric acid is added to sodium carbonate, limewater turns milky because of:

The white precipitate formed when silver nitrate solution is added to sodium chloride solution is:

Sodium carbonate is added to hard water in order to:

In a redox reaction, oxidation is:

In Zn + Cu²⁺ → Zn²⁺ + Cu, the reducing agent is:

In Mg + Br₂ → MgBr₂, bromine is:

Which is NOT one of the three sides of the combustion triangle?

Wet paper catches fire more slowly than dry paper because water:

The lowest temperature at which a substance starts to burn and continues burning by itself is its:

The substance in the matchstick head that supplies oxygen is:

Which oxide dissolves in water and turns litmus blue?

A yellow, smoky flame on a gas burner shows:

The complete combustion of methane gives:

How many oxygen molecules are needed to burn 3 methane molecules completely?

Anhydrous cobalt chloride paper changes from blue to pink in the presence of:

The brown, pungent gas formed from nitrogen oxides in air is:

Which gas with a choking odour is formed by burning sulphur-containing fuel?

The device in car exhaust that changes CO and NOₓ into CO₂ and N₂ is the:

The substance in tobacco responsible for addiction is:

Carbon monoxide in smoke is dangerous because it:

Passive smoking means: