Organic Chemistry> sir what about the vapour density n all.....

sir what about the vapour density n all...if the question is like this ,volume of STP of 0.34g of NH3 is..........n the number of molecules present in 11.2L of CO2 at STP is.....how should i go vth these kind of sums

neha bhandare , 9 Years ago

Grade 11

2 Answers

Neeti

Last Activity: 9 Years ago

Hello Neha,

The concept behind such questions is of mole concept. In the first question, the volume of 0.34g NH3 is asked at STP. We know that the volume occupied by one mole of a substance at STP = 22.4litres. and one mole of a compound is equal to it’s molecular weight. molecular weight of NH3 is 17 therefore 17g of NH3 occupies 22.4litres at STP. now by using unitary method you can calculate the volume of 0.34g NH3. which is 0.448litres.

Neeti

Last Activity: 9 Years ago

Sorry i missed the second part, it’s done the same way, you need to remember that one mole of a substance has 6.023 x 10^23 constituent particles which can be atoms or molecules. and one mole of a substance occupies 22.4lites, so basically 22.4litres of a substance has 6.023x10^23 particles. apply unitary method again and youll get 3.016x10^23 molecules.

and remember all of this is done at STP.