C2 Mixtures Flashcards
What are substances
They aren’t chemically joined just mixed up
How do you separate a compound
Using a chemical reaction
What are mixtures properties
The substance in the mixture keep their own properties
What are the properties in a compound
A compound has different properties to those of its elements
What is a pure substance
A substance is pure if it has no other substances mixed with it
What is an impure substance
A substance is impure if it has different substance mixed with it
How can you identify a pure substance
It will have a sharp melting point - it will stay at the same temperature until all the solid has melted
Are there other mixtures
Most materials are mixtures some are natural:
Most rocks are mixture of compounds
Seawater is a mixture of water, sodium chloride and other salts
What is a solvent
The liquid in which a gas or solid dissolves in
What is a solute
The solid or gas that dissolves in a liquid
How do you find out is something is in a solution
By colour
By mass - 1l of water = 1000g
Dissolve 20g of sugar
End mass- 1020g
Explain dissolving
Water particles surround each solute particle. The solute particles can mix with the liquid and they are arranged randomly and move around
Can gases dissolve
Yes- many gases dissolve in solvents
What is an example of gas dissolving in a solvent
Carbon dioxide gas makes drinks fizzy - when you open the bottle the gas leaves the solution
What is a saturated solution
A solution where no more solute can dissolve
How do you make a saturated solution of salt (sodium chloride)
Adding more that 36g of salt into 100g of water
What is solubility
The mass of solute that dissolves on 100g of water to make a saturated solution
What does insoluble mean
The word given to some substances that cannot dissolve in water (sand, chalk)
How can you dissolve more sugar into water
Heating up the water to a higher temperature
What is filtration
Separating a liquid from an insoluble solid
How does filtering work
You can separate same from water by pouring the mixture into filter paper - water passes through sand doesn’t
What is filtrate
The liquid or solution that collects in the container after the mixture has passed through the filter paper
What is residue
The solid that collects in the filter paper (sand)
How do people get salt from seawater
Evaporation- the sun transfers energy to the water molecules and they leave the surface of the solution
when all the water has evaporated, solid salt remains
What is distillation
A technique that uses evaporation and condensation to obtain a solvent from a solution
What do you need to preform distillation
Thermometer
Bunsen burner
Condenser beaker
Mixture (salty water )
How does distillation work with salty water
Water in the salt solution boils Steam leaves the solution Steam travels through the condenser and cold down The steam condenses into liquid water Liquid water drips into the beaker
What is chromatography
A technique to separate mixtures of liquid that are soluble in the same solvent (pen inks)
How is chromatography useful
To identify food nutrients
To figure out a forgery
