Filtering and evaporation How can we get clean water?
STARTER Match the equipment diagrams to the correct names. Beaker Evaporating Basin Pestle and Mortar Bung Conical Flask Spatula Pipette Measuring Cylinder
Aims Know some common uses of salt Plan a method for separating pure salt from rock salt. Carry out your planned purification.
Large amounts of salt are used everyday and these large amounts are often mined from the ground in the form of 'rock salt'. This is, as it sounds, a mixture of rock cgrahamphysics.com and salt.
What is a mixture? A mixture contains two or more substances that are mixed together, but have not chemically bonded with each other. For example, seawater is a mixture of water, salt and other substances. A pure substance contains just one substance on its own. For example, table salt (sodium chloride) is a pure substance. Can you name some different mixtures, and pure substances, that you might find in your house?
How could you separate these mixtures? Suggest some methods by which you could separate out these mixtures: l chocolate buttons and raisins l different coloured sweets l pebbles and sand l salt and sand l mud and water l oil and water l gold and iron.
Separating an insoluble solid How could you separate an insoluble solid like sand from a mixture of sand and water? It is easy to separate an insoluble solid by filtering the mixture. The insoluble solid cannot pass through the filter paper but the water can. The sand that is trapped by the filter paper is called the residue. The water that passes through the filter paper is called the filtrate. Filtering animation.swf
Filtering apparatus
Separating a soluble solid How could you separate a soluble solid, like salt, from a seawater solution? To separate a soluble solid from a solution, evaporation can be used. The solution is heated so that the water evaporates and leaves the dissolved solid behind.
Evaporation apparatus
Separate pure salt from rock salt How will you do it? Safety precautions? Write down a method 1. Take some rock salt and smash it up in a mortar 2. 3. and so on Draw a diagram of how we will assemble the equipment. Before you start..
Why did Group B get less rock salt from their sample than Group A? Slide 1 of 6
Slide 2 of 6
Slide 3 of 6
Slide 4 of 6
Slide 5 of 6
Slide 6 of 6
Dissolve You will be marked on: Pure white colour Mass of salt recovered Filter Evaporate How can we make more salt dissolve in less water? Give the water particles more energy so they work harder to split up the salt Use hot water from the kettle
Assemble your equipment A sample of rock salt Filter paper Funnel 2 x beakers Beaker + conical flask Bunsen burner Heatproof mat Tripod and gauze Watch glass
Plenary Sand, salt and water and iron are mixed together. Filtration, evaporation and separate using a magnet. How could you separate all three substances from each other? Write down a method in your book and what is removed at each stage.
Make flashcards, learn the spellings and find descriptions Soluble Solute Insoluble Solvent Pure Solution Evaporate Boil Filtrate Substrate Sodium chloride Condensation Distillation Chromatography Percoplate
Ideas about mixtures and solutions
Click on a person to see their idea. Which ideas are correct? Allie Chen Debbie Fran Mike James
Sugar melts when you put it into tea. Allie
Sugar melts when you put it into tea. Incorrect Sugar dissolves when you put it into tea. It makes a solution, which is a mixture of the sugar and the tea. Melting happens when you heat a substance on its own.
A solution is a mixture because the solid and liquid are jumbled up together. Chen
A solution is a mixture because the solid and liquid are jumbled up together. Correct
Tea doesn't have to be hot for the sugar to dissolve in it. Debbie
Tea doesn't have to be hot for the sugar to dissolve in it. Correct Sugar dissolves faster in hot tea, but it will still dissolve in cold tea.
If a solid dissolves in a liquid, we say the solid is an insoluble solid. Fran
If a solid dissolves in a liquid, we say the solid is an insoluble solid. Incorrect A solid that dissolves is described as soluble.
Salt disappears when you put it into water. Mike
Salt disappears when you put it into water. Partly correct The salt seems to disappear, because you cannot see it any more. However the salt is still there as you would find out if you tasted it!
In salty water, the salt is the solvent and the water is the solute. James
In salty water, the salt is the solvent and the water is the solute. Incorrect The solid that you add is the solute. The liquid you put it into is the solvent.