Every card in Chemical reactions, Year 7: more practice
The whole deck, in order — so you can read it through before your child ever sees it.
- Water boiling in a pan is full of bubbles. Why is this not a chemical reaction?
The bubbles are just water turning to steam, so no new substance forms
HintWhat is the gas in there, and where did it come from?
WhyBoiling is a change of state, a physical change. Steam is still water, so there is no new substance, which would be the sign of a chemical reaction.
- Bread dough bakes and its crust turns brown. Does the colour change suggest a chemical reaction?
Yes, a new colour suggests new substances have formed
HintCan the crust be turned back into dough?
WhyThe browning of the crust is made by new substances, and it cannot be undone. Unexpected colour changes are a sign of a chemical reaction.
- A fizzing reaction gives off a gas that relights a glowing splint. Which gas is it?
Oxygen
HintOnly one gas makes a glowing splint burst into flame again.
WhyOxygen supports burning, so a glowing splint relights in it. It is the standard test for oxygen.
- Which gas turns limewater cloudy?
Carbon dioxide
HintThe limewater reacts with the gas to form a fine white solid.
WhyLimewater turns cloudy because carbon dioxide reacts with it and makes tiny solid particles. This is the standard test for carbon dioxide.
- A candle burning in a sealed jar goes out after a short time. Why?
The oxygen is used up
HintBurning needs a gas from the air as well as the fuel.
WhyThe wax is still there, but the oxygen in the jar has been used up, so the burning stops.
- Magnesium ribbon burns with a bright white light and leaves a white powder. Name the powder (two words).
Magnesium oxide
HintThe metal combines with oxygen from the air.
WhyMagnesium + oxygen → magnesium oxide. The mass of the white powder is more than the mass of the ribbon, because oxygen has joined it.
- Is energy taken in or given out when a fuel burns?
Given out, as heat and light
HintThink how a campfire feels.
WhyBurning is a chemical reaction that releases stored energy. The fuel is the store of energy.
- Write a word equation for magnesium burning in oxygen.
magnesium + oxygen → magnesium oxide
HintReactants go on the left, the product on the right.
WhyThe arrow means 'react to make'. The word oxide shows oxygen has joined the metal.
- In the word equation zinc + sulfur → zinc sulfide, which substance is the product?
Zinc sulfide
HintThe product is on the right of the arrow.
WhyReactants are on the left of the arrow and the products are on the right. Zinc and sulfur are used up to make zinc sulfide.
- Say this word equation as a plain-English sentence: hydrogen + oxygen → water.
Hydrogen reacts with oxygen to make water
HintRead the plus as 'joins up' and the arrow as 'turns into'.
WhyA word equation is a sentence in shorthand: it says what goes in and what comes out.
1★ KS3-CHEM-REA-0035
2★ KS3-CHEM-REA-0036
3★ KS3-CHEM-REA-0037
4★ KS3-CHEM-REA-0038
5★ KS3-CHEM-REA-0039
6★ KS3-CHEM-REA-0040
7★ KS3-CHEM-REA-0041
8★ KS3-CHEM-REA-0042
9★ KS3-CHEM-REA-0043
10★ KS3-CHEM-REA-0044
Keep what you learn
Here, nothing is saved. In your child’s own sky every card is scheduled — it comes back just before they’d forget it — and the professor who wrote it is one tap away.