# Reversible and irreversible changes

> Grade 5: dissolving makes a solution, reversible changes (melting, dissolving), irreversible changes (burning, rusting, cooking), separating by sieving, filtering, evaporating.

Source: https://olyclass.com/library/science-g5-dissolving-changes-en/

- Subject: Science
- Level: Grade 5
- Quiz: 16
- Play it free on one screen (projector, TV or whiteboard): https://olyclass.com/library?play=science-g5-dissolving-changes-en
- Copy and edit it: https://olyclass.com/library?copy=science-g5-dissolving-changes-en
- Games it plays well in: [Paper Race](https://olyclass.com/classroom-games/paper-race/), [Three in a Row](https://olyclass.com/classroom-games/three-in-a-row/), [Line of Four](https://olyclass.com/classroom-games/line-of-four/), [Team Bingo](https://olyclass.com/classroom-games/team-bingo/)

## Questions

1. When sugar mixes into water and seems to disappear, what have you made? (A gas / A metal / A solid / A solution)
   Answer: A solution
2. In a salt solution, which word describes the salt? (Filter / Residue / Solute / Solvent)
   Answer: Solute
3. Sand dissolves in water to make a solution.
   Answer: False
4. Which change is reversible? (Baking a cake / Burning paper / Melting ice / Rusting a nail)
   Answer: Melting ice
5. Chocolate melts in the sun. What can you do to make it solid again? (Burn it / Cool it / Heat it more / Stir it in water)
   Answer: Cool it
6. What is the name for water turning into ice?
   Answer: Freezing
7. Which change is irreversible? (Dissolving salt in water / Freezing water / Frying an egg / Melting butter)
   Answer: Frying an egg
8. An iron nail left in wet air turns orange-brown. What is this called? (Dissolving / Freezing / Melting / Rusting)
   Answer: Rusting
9. Once wood has burned to ash, we cannot change it back into wood.
   Answer: True
10. Which tool best separates large stones from fine sand? (A magnet / A sieve / A spoon / A thermometer)
   Answer: A sieve
11. Muddy water is poured through filter paper. What stays on the paper? (All the water / Dissolved salt / Nothing at all / The solid mud)
   Answer: The solid mud
12. What word describes a material, like sand, that cannot dissolve in water?
   Answer: Insoluble
13. How can you get salt back from salty water? (Evaporate the water / Filter it / Freeze it only / Sieve it)
   Answer: Evaporate the water
14. Filtering can separate dissolved salt from water.
   Answer: False
15. To separate sand and salt, which liquid do you add to dissolve the salt?
   Answer: Water
16. Why can't a baked cake turn back into runny cake mixture? (Heat made new materials / It dissolved in air / It was filtered / It was only melted)
   Answer: Heat made new materials