IMO Practice Test — Matter & Its Changes
6 Questions • 12 min • Olympiad level
12:00
Question 1 of 6
hard
We can get the salt back from salty water by letting the water…
Freeze the salt away
Evaporate, leaving the salt
Burn
Dissolve more
Explanation: Evaporating the water leaves the salt behind.
Question 2 of 6
hard
Water is unusual because we easily see it as all three states:
Ice, water and steam
Only ice
Only steam
Only liquid
Explanation: Water appears as ice, liquid water and steam.
Question 3 of 6
hard
Iron slowly turning into reddish rust in damp air is an example of a change that is…
Irreversible
Reversible
Melting
Freezing
Explanation: Rusting forms a new substance and cannot be undone.
Question 4 of 6
hard
Mixing flour, water and baking it into a cake is irreversible because a ___ substance is formed.
Cold
New
Frozen
Wet
Explanation: Baking forms a new substance that cannot be un-baked.
Question 5 of 6
hard
Evaporation and condensation together keep happening in nature as part of the…
Light cycle
Food chain
Water cycle
Day cycle
Explanation: These changes drive the water cycle.
Question 6 of 6
hard
Different solids melt at different temperatures; butter melts easily but iron needs very great…
Light
Cold
Heat
Sound
Explanation: Iron needs far more heat to melt than butter.