Science yr8- Physical & Chemical Change Flashcards
What is matter
Matter is anything that takes up space and can be weighed
What are the 3 states of matter
Solid, Liquid, Gas
Is a change in state a phyiscal or chemical change
Physical
How do you change the state of an object
Energy is added or removed
What is change (Scientific definition)
Change is the act of altering a substance
What is Chemical change
It’s a rearrangement of particles so that the product is different to the reactants
What DOESN’T a Physical change do
It doesn’t change the chemical composition or identity of the substance, only the form
What are 5 examples of a PHYSICAL change
-MELTING ice
-FREEZING cordial
-TEARING paper
-BOILING water
-MIXING a mixture (ex. sugar+water)
What DOES a chemical change do
It does change the chemical composition or identity of a substance and makes a new substance
What are 4 examples of a CHEMICAL change
-BURNING paper (COMBUSTION)
-ROTTING (DECOMPOSING)
-RUSTING
-TEMPERATURE CHANGE (Endothermic & Exothermic reactions)
What are reactants
They are the substances reacting with each other
What is the product
The thing being produced at the end of the reaction
What is the formula for a CHEMICAL change
Reactant + Reactant= Product
What is the rule about matter
It’s never created or destroyed in chemical reactions
What is an Endothermic reaction
The heat moves into the system from the surroundings, so the surroundings get colder.
What is an Exothermic reaction
The heat moves out of the system into the surroundings, so the surroundings get hotter.
What are the 7 clues of chemical change
- Combustion (burning)
- Odour/smell
- Colour change (rusting)
- Irreversible
- Gas/bubbles
- Temperature change
- Light
What must CHEMICAL changes have
It must have a total rearrangement of particles. (The product is different to the reactants)
What is diffusion
The movement of particles, within a liquid or a gas, from an area of HIGH concentration, to an area of LOW concentration. Until the particles are evenly spread.
Which states of matter could diffuse
-Solid particles can’t move, they’re fixed. So they COULDN’T diffuse
-Liquid and Gas particles move freely. So they COULD diffuse
-To get a solid to diffuse, you have to DISSOLVE it.
What is the ‘Brownian Motion’
The RANDOM movement of a particle as a result of bumping into other liquid or gas particles. This movement always flows from high concentration to low concentration.
What are the 4 factors affecting the diffusion rate
- Temperature
- Density
- Volume
- Pressure
