C1, C2 Flashcards
What is an element?
All the atoms are the same
What is a compound?
When you chemically combine 2 or more elements
What is a fixed proportion?
For every one atom of an elements there is another atom
How do you turn compounds back into their elements?
Make a chemical reaction
What is a mixture?
When you have different elements or compounds but not chemically combined
How do you seperate a mixture?
By using filtration,distillation or crystilisation
What can physical seperation techniques be only used to seperate?
Mixtures
What is filtration used to seperate?
An insoluble solid from a liquid
What does insoluble mean?
Not dissolve in the liquid
What equipment do you need for filtration?
- Filter funnel
- Filter paper
- Conical flask
What is crystilisation?
Used to seperate a soluble solid from a liquid
What are the steps of crystalisation?
1) Pour the solution in a evaporating dish and heat the dish. Some will evaporate, some willget more concentrated
2) Once some of the solvent has evaporated or when you see crystals start to form. Remove the dish from the heat and leave the solution to cool
3) The salt should start to form crystals and becomes insoluable in the cold
4) filter the crystals out in the solution and leave them in a warm place to dry
What is the disadvantage of crystilisation?
When you heat them chemicals will break down
What is simple distilation great for,?
Seperating salt water from drinking water
What is simple distilation good for?
When you want the solid and the liquid
Whats the equipment for simple distillation?
- Themometer
- Condenser
- Pot
- Receiver flask
What are the steps for simple distilation?
1) Solution is heated and the part that has the lowest boiling point evaporates first
2) The vapour is cooled and condensed and turned back into a liquid and collected
3) The rest of the solution is left in the flask
Whats the main disadvantage of using simple distilation?
You can only seperate things with different boiling point
Whats the equipment for fractional distilation?
- Pot
- Themometer
- Condenser
- Fractionating column
- Beaker
Disadvantage of using fractional distilation?
- When theyre similar temperature you need to carry out more rounds of fractional distilation
- The equipment is not useful when you want to seperate large volumes of liquid
Steps for fractional distilation?
1) Put the mixture in the pot/flask with a fractionating column on top and heat it
2) The liquid with the lowest boiling point evaporates first and when the themometer matches the boiling point you know it’s reached the top
3) Liquids with high boiling points might start to evaporate but the column is coller at the top so they will run back down.
4) Put a beaker and collect the 2 chemicals
What are physical processes?
Dont involve chemical reaction and no new substances are made
What does chromatography help you do?
Seperate differnt substances based on their solubilities
What do you call the paper in chromatography?
The stationary phase
What do you call the solvent in chromatography?
Mobile phase because the solvent moves
What will a pure compound produce is chromatography?
A single spot in solvents
What will a mixture produce in chromatography?
Seperate into differnt spots
Why does paper chromatography work?
Differnt substances have differnt sollubilities
Why do you draw the starting line in pencil chromatography?
The pen ink will disolve and the solvent in it will move up the paper