i have the Mr of lead nitrate 331 and i thermally decompose it giving nitrogen dioxide and oxygen. i want to collect exactly 200cm3 of the gases evolved in a syringe. what mass of lead nitrate should i take ?

Answer 1

Here is a worked example of a stoichiometry problem. Just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html

Answer 2

can you do it for me if possible drbob222 ?

Answer 3

I will be glad to help you through it if you have trouble. Post your work and explain what you don't understand.