chemistry help?

Question

6. Given the following equation:2 NaClO3-->2 NaCl + 3 O2
12.00 moles of NaClO3 will produce how many grams of O2? How many grams of NaCl are produced when 80.0 grams of O2 are produced?

7. Given the following equation: Cu +2 AgNO3--> Cu(NO3)2 + 2 Ag.
How many moles of Cu are needed to react with 3.50 moles of AgNo3? If 89.5 grams of Ag were produced, how many grams of Cu reacted?

8. Molten iron and carbon monoxide are produced in a blast furnace by the reaction of iron(III) oxide and coke (pure carbon). If 25.0 kilograms of pure Fe2O3 is used, how many kilograms of iron can be produced? The reaction is: Fe2O3 + 3 C--> 2 Fe + 3 CO.

Answer 1

I will only give you this hint:
Number of moles of molecules=(mass in gr)/Molecular weight
=Number of molecules/Avogadro number.
Molecular weight = Sum of Atomic weights of all the atoms involved.
Assume all substances react stoicheiometrically.