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molecular weight

Posted: Mon Sep 12, 2011 9:11 pm
by akekilova
I need to calculate what volume of oxygen would be required to burn 100 g of propane.
I've got that it is 363,64 g of O2 for 100g of C3H8

then I use Ideal gas law to find the volume V= nRT/P
n= 363,64 g /32 g/mol
here is a question. We need 5 moles of oxygen for 1 mole of propane. Should I calculate n with 32 g/mol of O2 or I need 5O2=160 g/mol

Please advice

Posted: Tue Sep 13, 2011 1:12 pm
by expert
Molar volume of any gas at normal conditions is 22,4 L. That's the law. To find the volume of 5 mols of oxygen just simply multipy 5x22,4