Graphing Activities for Chemistry

Hi, I'm Robin Higgins and this is graphing activities for chemistry. Alright so there's a bunch of different graphs that we use in chemistry, but let's go over a couple different types. The first is the relationship between pressure, volume and temperature. So let's imagine we have some kind of gas in a container that can expand and contract. And let's say that we are measuring pressure. So now if we are measuring pressure and we are slowly increasing it, now it's going to be getting tighter and tighter and tighter and tighter and so that means that the volume is going to actually be getting smaller. So the relationship between volume and pressure is like this, if one gets bigger the other gets smaller. Now, let's graph pressure versus temperature. If you increase the pressure, there is going to be more energy added and the molecules will be moving more quickly and that actually increases the overall energy which includes the temperature. So, between temperature and pressure, if one increases, the other increases. Now the other type of graph I want to draw for you is a phase change diagram. And this is where we're going to add heat and measure the temperature. So if we start with very low heat and let's say that we are doing a phase change diagram of water and this is an ice cube, at first the amount of heat we get will all go into raising the ice and then at a certain point, the temperature will stop increasing and it will be completely horizontal like this and this means that the ice is melting. So during a phase change, all of the heat goes into breaking down the interactions in between water molecules and there is no temperature change but once all of the ice has melted, you'll start increasing the temperature again. So, this is now just water heating. And now, once we reach this next point, the boiling point, once again all of the heat we are adding just goes in to making sure those water molecules start to separate and the temperature doesn't raise at all. And now here, you're going to have pure steam and now you can just continue to raise the temperature as much as you want. So, ice, liquid and gas. Alright, remember there's lots of other chemistry graphs but these are different types are very important. I'm Robin Higgins and this is graphing activities for chemistry.