Sciencemadness Discussion Board

Looking for a guide to Stoichiometry

freedompyro - 20-6-2011 at 11:33

I'm trying to wrap my head around it for oxygen balancing and wondered if anyone could suggest a book/online guide to how to do it?

Sucrose (C12H22O11) - 342.30 g/mol
Potassium Nitrate (KNO3) - 101.1032 g/mol

My vague idea of it is that I need to get the weight of carbon, hydrogen and oxygen in the sucrose... So that I know exactly how many grams of each there is...

And get the weight of the potassium, nitrogen, and oxygen for KNO3. But, to solve this I also need the reaction equation? Just beginning to study O-Chem a bit in my free time.

Bot0nist - 20-6-2011 at 11:59

http://cavemanchemistry.com/oldcave/projects/stoich/index.ht...

A good place to start.

LanthanumK - 20-6-2011 at 13:37

Add the individual atomic masses (found as atomic masses on the periodic table) for a molecule to find its molecular mass, which is the same number as molar mass. So for KNO3 add the atomic mass for 1 K, 1 N, and 3 O to get the number for KNO3.

Atomic mass is atomic mass units/atom; molar mass is grams/mole. They have the same number although they have different meanings.

watson.fawkes - 21-6-2011 at 10:07

Quote: Originally posted by LanthanumK  
Atomic mass is atomic mass units/atom; molar mass is grams/mole. They have the same number although they have different meanings.
To remember approximately what an atomic mass unit is, it's approximately the mass of a proton (within a percent). So one mole of protons weighs approximately one gram. Just counting the protons and neutrons in a molecule gives a good estimate of its actual mass. This disregards nuclear binding energy, but is good for a mnemonic as well as quick estimates.

leu - 21-6-2011 at 11:00

Laborant will do the calculations:

http://www.sciencemadness.org/talk/viewthread.php?tid=4794#p...

as far as your specific question:

http://www.sciencemadness.org/talk/viewthread.php?tid=52#pid...

the search engine is your friend :cool: