Chemistry Solutions and Mixtures

Chemistry Solutions and Mixtures

1. Mixtures

   • How are mixtures and compounds different?
     • The elements in a mixture are not chemically bonded.
     • The elements in a compound are strongly joined together and you can not separate without a chemical reaction
     • How can you identify pure substances?
       • A pure substance has a very high melting point

2. Solutions

   • Does a solute disappear when it dissolves?
     • Some solutions are coloured this means when mixed with the solution you can see a colour this means the solute is still there
   • How can we explain dissolving?
     • when sugar dissolves in water water particles surround the sugar particles mix with the solution and move around and re arrange randomly
   • Can gases dissolve?
     • yes many gases can dissolve in solvents for example carbon dioxide makes drinks fizzy when the bottle is open the gas leaves the solution

3. Solubility

   • How does temperature affect solubility?
     • the higher the temperature the greater the mass dissolves
   • What is Saturation?
     • when you add spoonfulls of sugar to a solution at one point it will be saturated this means the solute will reach the bottom of the solution

4. Filtration

   • How does filtiring work?
     • you can seperate sand from water by using the method of filtration this means water passes through the filter but the tiny holes stop the sand from passing through
       • the water that passes through is called the filtrate and the residue is the sand which does not pass through

5. Evaporation and distillation

   • evaporation is useful to seperate salt from sea water
     • the sun transfers energy to the water molecuels and they leave the surface of the solution when all the solution evaporates we have our solid salt remaining
   • What is distillation?
     • distilllation is a process that uses evaporation and condensation to obtain a solvent from a solution
     • It works like this: water in the salt solution boils, steam leaves the solution, steam travels through the condenser and cools down, steam condenses and forms a liquid and liquid water drops into the beaker.

6. Chromatography

   • how does chromatography work?
     • Chromatogrphy is used to find out what dyes are in what colours
       • Chromatography seperates substances in a mixture it works when substances in a mixture are soluble in the same solvent.