calculate the volume of Nitrogen gas generated at 21 degree celcius and 823 mmHg by the decomposition of 60.0 grams of sodium nitrate?

2 answers

Heating NaNO3 produces O2 and not N2. Did you mean N2? If so, then
2NaNO3 ==> 2NaNO2 + O2
mols NaNO3 = grams NaNO3/molar mass = 60/approx 85 = about 0.7
Since 2 mol NaNO3 will produce 1 mol O2, then 0.7 mol NaNO3 will produce 0.7/2 = approx 0.35 mol O2.
Then use PV = nRT so solve for the volume.
NOTE: I have estimated all of the numbers. They are close. You need to do them more accurately. Post your work if you have trouble.
That was my comment also: what do you mean by decomposition? real world, or some fake chemical decomposition given as a teacher thinking problem. Sodium nitrite is very stable, and it (to my knowledge) does not decompose.