KS3 Chemistry Study & Question Book (CGP KS3 Study Guides)

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And in one of those great moments in history where knowledge and opportunity coincide, scientists realised that a vast source of raw ingredients for these new plastics had already been discovered. Before long, the water level drops. Even after we take the heat away, the liquid continues to evaporate, leaving crystals of salt behind. Gethin : What about diffusion? Can happen in all states? And by that I mean solids, liquids and gases? Chromatography is a technique used to separate soluble substances that have been mixed together. It’s normally used to separate coloured mixtures, like food colourings.

At the solution’s boiling point, the high energy water molecules break free of the liquid surface, forming water vapour.Follow these steps to try out standard chromatography. You will need: a pencil, a ruler, a piece of paper, a coloured mixture such as a food dye. For example, sand is insoluble in water. We can separate insoluble solids from a solution using filtration. Filter paper has thousands of tiny holes that allow the liquid molecules to pass through. Teacher: The salt lowers the freezing point of the ice and, if you look closely, you will see the ice begin to melt. You can see this science in action when salt is spread on roads and pavements in freezing weather. It melts the ice, making it safe to drive or walk on. To balance the equation, you need to adjust the number of units of some of the substances until we get equal numbers of each type of atom on both sides. You should never change the formula of a substance to do this. Miss Roberts: So I want you to put that bottle of water, please, on to the scales and tell me what it says in grams.

This is unbalanced because there is one copper atom on each side of the arrow, but two oxygen atoms on the left and only one on the right. Katie: That's amazing. So, when water freezes it makes the atoms rearrange themselves so the result is the ice. But, because atoms can't be destroyed, the ice still has the same amount of stuff in. It just looks completely different. 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.

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By heating the water to boiling point, we have decreased the solubility of the dissolved gases. They come out of the solution as bubbles and the remaining water has less gases dissolved, so is less cloudy. VOICEOVER: The particles that make up gases and liquids move randomly. This movement allows the action of diffusion to happen.