Ethylene glycol, C2H6O2, is used as antifreeze for automobile engines. If you want to produce 2.00 kg of ethylene glycol from the reaction of C2H4Cl2 and Na2CO3, what is the minimum amount of Na2CO3 that is needed?

C2H4Cl2(l) + Na2CO3(s) + H2O(l)=C2H6O2(l) + 2NaCl(aq) + CO2(g)

2 answers

mols ethgl = 2000 g/molar mass ethylene glycol.

Convert mols ethylene glycol to mols Na2CO3 with the help of the coefficients in the balanced equation.

Finally, g Na2CO3 = mols x molar mass.

Here is a worked example which follows these steps. Memorize how you do this.
1. Convert g of what you have to mols
2. Convert mols of what you have to mols of what you want.
3. Convert mols of what you want to grams.
http://www.jiskha.com/science/chemistry/stoichiometry.html
2140.96