in today's video we're going to take a look at state symbols and see how we can predict which state of substance will be in at a particular temperature when we write chemical equations we sometimes need to show which state each substance is in and to do this we use state symbols so for solids we put an s for liquids we put an l and for gases we put a g sometimes though you'll have a substance that isn't in one of these pure states and instead is dissolved in water which we call aqueous so for this we put aq for example if we put some sodium in water it would form sodium hydroxide and hydrogen as sodium is a metal it would be solid at room temperature which would show by writing an s in brackets after the n a and then would put an l after the h2o to show that it's a liquid the sodium hydroxide is a bit more difficult it's basically an ionic compound that's dissolved in the water so it's no longer solid but it's also not a pure liquid so instead we call it aqueous and write hu then finally the hydrogen will be given off as a gas which we show with a g in your exams you might be asked to predict which data substance would be in at a certain temperature for these they'll normally give you some data like in this table and then ask you questions based on that information for example what states are water copper and magnesium in at 800 degrees celsius one way to conceptualize this stuff is to imagine the temperatures on a number line so for water we can see that this melting point is at zero degrees and the boiling point is 100 degrees so anything below zero degrees and the water will be solid ice because it hasn't melted yet then at zero degrees it melts into a liquid and it will stay liquid for all temperatures up to 100 degrees at which point it boils and becomes gaseous water vapor and stays the gas as we increase the temperature further so at 800 degrees water would definitely be a gas then for copper we can see that it doesn't melt until 1083 degrees so at 800 degrees it must still be a solid and finally magnesium has a melting point of 650 degrees and a boiling point of 117 degrees so it'll be between the two and so a liquid anyway thanks for watching if you enjoyed the video then please do give us a like and subscribe and we'll see you next time