Solutions

Solutions

1. Some solids dissolve in water to make a solution. These solids are soluble. A solution is made from a solute(solid) and a solvent (liquid).When a solution is formed, the liquid is always transparent.

   • Solids that don't dissolve are insoluble. when an insoluble solid is mixed with water, the water goes cloudy and the solid will sink to the bottom.
     • The total mass of a solution is the mass of the solute(solid) added to the mass of the solvent (liquid)
       • Water is the most common solvent it is easily available, cheap and dissolves a lot of different solutes.

2. If you keep adding solutes to a solvent, you will get to a point where no more will dissolve. A saturated solution cannot dissolve any more solute. More solid will dissolve if you add more solvent (e.g. water) or increase the temperature.

3. filtering is used to separate solid particles which don't dissolve from the liquid they are in. (e.g. sand from a mixture of sand and water)

   • evaporation is used to dissolve substances from a solution (e.g. salt from salt solution)
   • distillation (evaporation followed by condensation)it is when the liquid from the dissolved solid in a solution or one liquid from a mixture of liquids. (e.g. water from salt solution)
   • Chromatography is used to separate individual colours from a mixture of colours (e.g.the colours found in ink)

4. Simple distillation-This method works because the water evaporates from the solution, but is then cooled and condensed into a separate container. The salt does not evaporate and so it stays behind

5. Fractional distillation This is good for separating two or more liquids from each other. For example, ethanol (alcohol) can be separated from a mixture of ethanol and water by fractional distillation. This method works because the two liquids have different boiling points.

6. Evaporation This is good for separating a soluble solid from a liquid (a soluble substance does dissolve, to form a solution). For example copper sulphate crystals can be separated from copper sulphate solution using evaporation. Remember that it is the water that evaporates away, not the solution.

7. Filtration is good for separating an insoluble solid from a liquid. (An insoluble substance is one that does not dissolve). Sand, for example, can be separated from a mixture of sand and water using filtration. That's because sand does not dissolve in water.

8. Chromatography This is good for separating dissolved substances that have different colours, such as inks and plant dyes. It works because some of the coloured substances dissolve in the liquid better than others, so they travel further up the paper