hi chemists in this video we are going to focus on the relationships between units of pressure and temperature and kinetic energy after this video you should be able to convert between units of pressure and explain what mathematically would occur if the average kinetic energy and temperature changing gas pressure as you may recall is the simultaneous collisions of gas particles and we talked about popcorn popping with gas pressure and pressure is measured in different units atmospheres kilo Pascal's and millimeters of mercury all pressure conversions can be done in a single dimensional analysis conversion so here's an example so it says the pressure inside a balloon is four point one seven atm how many kilo Pascal's is this just like we always do we'll start with our known and our unknown and we'll take our known put our multiplication sign in and you want to ask yourself the question what conversion factor are you using we know that 1 atm equals 760 millimeters of mercury which also equals 101.3 kilo Pascal's but we don't you can't use all three of these so we are going to focus on the fact that 180 M equals 101.3 kPa because our known is an ATM and our unknown is Inc in kPa so we will take our 1 atm put it on bottom and then 101.3 kPa is going to go on top we're then going to have to do our multiplication and the number of sig figs is going to match the number in the known so it should be 422 kilo Pascal's as our answer if the calculation were different and it asked for how many millimeters our mercury this would be equal to fortunately the setup is the same the only difference is on the top here you would just replace the 101.3 kPa with 760 millimeters of mercury in a sample of mater it's important to note that not all particles are moving with the same speed and so temperature as we mentioned is a measure of the amount of kinetic energy that a sample of matter has and it is true that most particles are moving with the average kinetic energy however some are moving slower and some are moving faster so that's why not all particles in a sample have the same amount of kinetic energy and so if you look at this sample on the right hand side here you can very clearly see that there are some particles that are moving much slower and some particles that are moving very fast and you can also see that in this graph right here notice the Y is number of molecules you can see that in the center of this curve this is really your average so for example in a gas you can see that most particles are moving with an average speed however some on the right hand side are moving faster than average and some are moving slower than average as you increase temperature the speed of the molecules is going to increase so notice that this red line indicates a hot gas and you're going to see the speed of those particles increase and so the average speed is going to be greater as a result of the temperature being greater average kinetic energy is directly proportional to the Kelvin temperature and what that means is is that the factor by which your kinetic energy would go up that would be the factor by which your temperature would go up as long as it's in Kelvin so it's important to note how to figure out what the temperature would be in Kelvin and so fortunately it's a really easy calculation all you have to do is take the degree Celsius temperature and add 273 to it Kelvin it's important to note Kelvin is never a negative number so you should never get a negative answer when you're doing this so for example we know room temp is equal to the 25 degrees Celsius approximately what is this in Kelvin you would take the 25 degrees Celsius and add 273 and you would get 298 Kelvin notice that's written as 298 K it's not written as 298 degrees K there's no degree sign included in Kelvin as temperature decreases we know that the particles will continue to move slower and slower so we may say that particles would theoretically stop at this temperature called absolute zero and absolute zero is zero Kelvin but we know that according to an etic kinetic molecular theory all particles are matter are in constant motion at this point too can absolutely row may or may not have been reached I know when I first made this power point became very very very very close but I'm not sure if we've reached yet but you might want to maybe do some research if you're interested standard temperature and pressure remember is abbreviated STP standard temperature and pressure will equal 0 degree Celsius or 273 Kelvin so now we're going to talk about calculating the factor by which kinetic energy changes given a temperature so so since kinetic energy is directly proportional to the Kelvin temperature the factor by which kinetic energy increases or decreases can be easily calculated so for example if your temperature goes from 200 Kelvin to 400 Kelvin then the average kinetic energy will double so if you do 400 over 200 you'll get it by a factor of 2 you want to when you're doing this always put the final temperature over the initial temperature that'll make it easier for you to tell what it should be here's another example if temperature goes from 100 to 300 then the average kinetic energy will triple and so 300 over 100 is how we show it mathematically so that'll be 3 if temperature goes in the opposite direction from 300 to 100 then the average kinetic energy will be a third so you do 100 over 300 and that will be one third here's another one if temperature goes from negative 73 degrees Celsius to 127 degrees Celsius then the average kinetic energy will be careful here kinetic energy is proportional to the Kelvin temperature not degrees Celsius so that means for you is you need to convert both of these temperatures into Kelvin and you can see this is a similar example from before it'll double and again 400 over 200 will give you 2 so I hope this video was helpful in under standing how to convert in between units of pressure and what the relationship is between kinetic energy and the Kelvin temperature thank you so much for watching