Calculating Avogadro's Law | Chemistry Homework in 3 MINUTES

0:00 hi i'm josh and this is a science classroom in this video i'm going to talk about how to solve a problem involving avogadro's law avogadro's law describes the relationship between the volume and the amount of a gas when the temperature and pressure are held constant using words avogadro's law can be described like this if the amount of a gas increases the volume of the gas will increase using an equation to be described like this v1 over n1 equals v2 over n2 basically this is showing the relationship between two sets of conditions the before conditions are represented by the ones and then after some change occurs the conditions are represented by the twos the v's stand for the volume of the gas and the n stands for the amount of the gas and it's in units of moles this equation has four variables and for chemistry

0:46 homework you are usually going to be given three of the variables and then you'll solve for the fourth unknown variable here's the kind of homework question you would need to solve for your chemistry class 1.48 moles of oxygen gas fill a balloon to 23.2 liters what would the new volume be if the amount of the gas increased to 2.10 moles assume the temperature and pressure were kept constant before i start to solve a question like this i like to organize the information i'll use red to highlight what the question is asking me to solve for it says what will the new volume be i like to write in the symbol from the equation so i can keep track of everything so v2 because this is going to be the volume when the conditions change next i'm going to use green to highlight the given information the starting conditions are given first there are 1.48 moles of oxygen gas

1:31 that's n1 with an initial volume of 23.2 liters i'll label that v1 remember that the ones are the starting or the initial conditions then something changes in this case the amount of gas changes to 2.10 moles so i'm going to label that n2 now i'm going to write down the equation v1 over n1 equals v2 over n2 i need to do some rearranging because i want to solve for the unknown which is v2 i need to get rid of n2 on this side and get it to the other side so i'll multiply this side by n2 to cancel it whatever i do to this side of the equal sign i have to do the other side so my equation will become v1 times n2 over n1 equals v2 now i can plug in all the variables that i've already labeled v1 is 23.2 liters

2:17 n2 is 2.10 moles and n1 is 1.48 moles i'll plug all of this into my calculator 23.2 times 2.10 and then i'll divide that by 1.48 i'm going to round my answer to three digits because each of the given variables has three significant digits and so my answer is 32.9 and the unit is liter because liter is the unit for volume thanks for watching if this video helped you out please give it a like and subscribe to the channel you