OCR Gateway GCSE Combined Science A chemistry reactions and analysis overview quiz quiz

A salt and hydrogen gas only and nothing else

A salt, water and carbon dioxide

Just a salt and water and nothing more

Only a salt with no other product at all

The gain of electrons

The gain of protons

The loss of electrons

The loss of neutrons

Breaking bonds releases energy and making bonds takes in energy

Both breaking and making bonds release energy

Neither involves energy

Breaking bonds takes in energy and making bonds releases energy

To the cathode, where they gain electrons

To the anode, where they lose electrons

To the cathode, where they lose electrons

They do not move

Because electrolysis is always the cheapest way to extract aluminium

Because aluminium is more reactive than carbon, so carbon cannot reduce it

Because there is simply no naturally occurring ore that contains aluminium

Because carbon is more reactive than aluminium and readily displaces it

Nothing happens at all, because iron is less reactive than the copper in the solution

The iron nail simply dissolves away completely with no other visible change taking place

Iron displaces copper: the blue colour fades and a copper coating forms on the nail

Copper displaces the iron from the nail and the solution slowly turns colourless

A lighted splint gives a squeaky pop

It relights a glowing splint

It turns limewater cloudy

It bleaches damp litmus paper white

Because the particles move faster, collide more often, and more collisions have enough energy to react

Because the individual reacting particles themselves swell right up and physically get bigger when heated

Because the activation energy needed for the reaction steadily increases as the temperature rises

Because the particles stop colliding with each other altogether once the mixture becomes hot enough

2 mol

0.5 mol

800 mol

20 mol

The reaction has completely stopped and nothing more is changing in the closed system

Only the forward reaction is still happening while the backward reaction has fully stopped

The forward and backward reactions happen at the same rate, so the amounts stay constant

All of the reactants have now been completely used up and turned into products