Solutions

Dissolving race (animation may not work on all computers)

Solutions A solution is a mixture...usually a mixture of a solid and a liquid e.g. salt and water But it can be 2 liquids like milk and tea = solution Or a gas and a solid like air and sugar(marshmallow)= solution

Some chemicals seem to disappear when they are stirred with water. Example: When sugar is put into water or tea it seems to disappear. When this happens, we say the substance has dissolved.

Solubility? A substance which dissolves is called a soluble substance. Eg. Salt and water A substance that does not dissolve is called an insoluble substance. Eg. Oil or sand and water

Dilute vs. Concentrated If there is lots of solute in the solvent then it is concentrated e.g. strong mi-wadi If there is very little solute compared to the solvent then it is dilute e.g. very weak mi-wadi

Which one is the solvent? _____ When any substance dissolves, we say that a solution has been made. the substance that has dissolved is given a special name. It is called the solute. Salt and water: Which one is the solute? Which one is the solvent? _____ The substance (usually liquid) that the solute dissolves in is called the SOLVENT

Solute, Solvent and Solution

What if the solid doesn’t dissolve? It’s insoluble Insoluble substances form a suspension with water. A suspension is cloudy. So the solid will fall to the bottom after a few minutes!!

Solvent It is not just water that dissolves things, any liquid which dissolves things is called a solvent. Water is a solvent, so is petrol and nail varnish remover. You will meet many more solvents throughout your life. Eg.__________________

Re-cap A solution is a mixture of a soluble substance (solute) and a solvent. A solute is _________________________ A solvent is________________________

Is there a limit to how much solid can dissolve? We know we can add a spoon of sugar to a cup of hot tea and it will dissolve. What would happen if the tea were cold? If we carry on adding sugar, there will come a point when the sugar will not dissolve in the tea, because there isn’t any more room for the sugar molecules. Points to note are; that when a solid is added to a liquid, eventually no more will dissolve, that different masses of different solids dissolve in the same volume of a particular solvent, that solids can dissolve in liquids other than water.

If we were to put salt into the same volume of tea the maximum number of tea spoons that could dissolve in the tea would be different. What would happen if the liquid was NOT tea? A saturated solution is one in which no more substance will dissolve in the liquid. A saturated solution contains as much dissolved solute as possible at that temperature