Physical Changes Flashcards
When does evaporation occur?
At any temperature between the melting and boiling point
Heat causes solids, liquids and gases to…
Expand
For a liquid to turn into a gas it must…
Boil
Two liquids were mixed together in a test tube. Which one of these would NOT show that a chemical reaction had taken place?
One of the liquids floated on top of the other
Why does a can containing aerosol gas explode when placed on a fire?
When particles are heated they vibrate which makes the compact can explode as there is not enough room for the particles to move around
What happens to railway tracks when they are heated in summer?
They expand because the energy of the heat (sun) has caused the particles to vibrate
Why does the level of sea change when it is warmed?
The sea expands because it has lots of kinetic energy which makes the thermal expansion greater
Give an example of a change which is a chemical reaction
Frying an egg
What is the solvent when you add salt to water?
Water
Is making yoghurt from milk a chemical change?
Yes
Is boiling water in an electric kettle a chemical change?
No
Is burning petrol in a car engine a chemical change?
Yes
Is diluting orange juice with water a chemical reaction?
No
Is making aluminium cans from a block of aluminium a chemical reaction?
No
How could you tell from a diagram that the substance is a gas?
The particles would be spread apart
