Year 10 Seperating Techniques Flashcards
(25 cards)
What is a mixture?
A mixture is made up of two or more substances which are not chemically joined together.
Define solute.
Solid that can be dissolved by a solvent.
Define solvent.
Liquid that can dissolve a solute.
What is a solution?
The mixture that forms when a solute is dissolved in a solvent.
What does soluble mean?
Can be dissolved in water.
What does insoluble mean?
Cannot be dissolved in water.
What is the residue in filtration?
The insoluble solid collected on the filter paper.
What is the filtrate in filtration?
The liquid that passes through the filter paper.
Describe the filtration process.
The mixture is poured onto filter paper; insoluble solids are collected as residue, and the liquid that passes through is called the filtrate.
What is the process of evaporation?
The solution is heated to remove the solvent, leaving the solute behind.
What is the purpose of grinding rock salt in the practical?
To increase its surface area to help it dissolve faster.
How is pure salt obtained from rock salt?
By grinding, filtering to remove insoluble sand, and evaporating the water.
What is the formula for percentage purity?
% purity = mass of pure salt / mass of rock salt x 100
What is distillation used for?
To separate a solution into its components based on different boiling points.
Describe the process of distillation.
The solution is heated, the solvent evaporates, and vapour is condensed back to liquid in a water-cooled condenser.
What is fractional distillation?
A process used to separate a mixture of liquids with different boiling points.
How does fractional distillation work?
Crude oil is heated, vapours rise through a fractionating column, and different fractions condense at different heights.
What are common end products of fractional distillation of crude oil?
- Fuels (e.g. petrol, diesel) * Solvents * Lubricants * Detergents
What happens to long-chain hydrocarbons during fractional distillation?
They condense at the bottom of the column where the temperature is highest.
What is a separating funnel used for?
To separate immiscible liquids based on different densities.
How do you collect liquids using a separating funnel?
Open the tap to collect the higher density liquid first, then close it and collect the lower density liquid.
What technique is used in paper chromatography?
It separates components based on their different rates of movement through a medium.
How do you calculate the Rf value?
Rf = distance travelled by the component / distance travelled by the solvent.
What should Rf values always be less than?
1
