Sometimes, near the top of the glass, the water particles will be going fast enough to escape into the air. Other compounds are made from different combinations of atoms, like water… carbon dioxide… and table salt. Mrs Roberts: Yeah. So, a displacement reaction involves a metal and a compound of a different metal. In a displacement reaction a more reactive metal will displace, which means pushes out, a less reactive metal from its compound. Dr. Tim: That's called the filtrate. And the filtrate is slightly clearer than before, though, it is still a little bit cloudy. And that's because some of the smaller pieces of sand have managed to pass through the filter paper into the water.

Gethin : What about diffusion? Can happen in all states? And by that I mean solids, liquids and gases? At the solution’s boiling point, the high energy water molecules break free of the liquid surface, forming water vapour. Put some water into your beaker just deep enough that the very end of the paper goes into the water. Only handle the heater by the outer casing. Where possible, avoid handling the heater once it is switched on. Give the heater time to cool after it is switched off.You will notice that the paper absorbs the water and it rises up the chromatography paper past the spots of food colouring. When the water reaches the spots, the pigments will dissolve in the water and move up the paper. Now, here we go. I don't know if you can see, but the container now contains style slightly clearer water at the bottom. And left in the filter paper here at the top, if I show you, is loads of the sand. Look at that, most of the grains are there and it's filtered through to the bottom.

Mrs Roberts: Yeah, well a lot of the time students like to think the more reactive element as being stronger and win in a fight with a less reactive element. It's OK to think of it as two metals fighting over a non-metal and winning if that helps you to remember. But you should never use the word stronger. The solubility of a solute in a solvent changes with temperature. And importantly, it depends on whether the solute is a gas or a solid. So, let's look at solids first. We’ll put the Bunsen burner under here and a cylinder to collect the water formed as the water vapour condenses. Plastics are polymers and that's Greek for many parts. So they're a bit like this chain of paperclips. They're individual components linked together. Ben: OK, some filtration. Sure thing. So I'm going to pour this carefully. I'm just going to try and get the sand.Solutions are a mixture in which a solid or a gas has completely dissolved in a liquid. We called the solid a solute and the liquid a solvent. A solid that will not dissolve in a specific liquid is described as insoluble. For example, if you spray some deodorant in your bedroom. The particles move from an area of high concentration, the place where you sprayed it, to an area of lower concentration - your bedroom doorway. Then, through the rest of the house. The perfume particles have diffused.

In this one you can see a tiny bit of sugar has crystallised at the bottom because it's a bit cooler. But this one, look how much sugar is actually in the bottom. The sugar behaves like most solids - the solubility increases as the temperature of the solvent does. Keep apparatus away from the edge of the table and make sure it is as stable as possible. For example, by resting the glassware on a flat surface.Elements can be placed into a reactivity series with the most reactive element at the top of the list and the least reactive at the bottom. A displacement reaction occurs when a more reactive element displaces, or pushes out, a less reactive element from a compound that contains the less reactive element. After a displacement reaction, the less reactive element is now pure and left uncombined. In industry, we use iron to displace copper from solutions of waste copper compounds, which is really useful. As scrap iron is much less valuable than copper, which we need for many electronic devices such as computers and phones. In the example above (the reaction between copper and oxygen to make copper oxide), we get this in the first step: As we've just seen, the rate of evaporation can be increased by heating the solution. So, if I left some of the salt solution on a sunny windowsill, the heat from the sun would warm up the water and slowly it would evaporate into the air.