You have already gotten the balanced equation. And the ratio of mol number of reactants and production is the ratio of coefficient. So there is 6.4/8*11=8.8 mol oxygen needed. The mass is 8.8*32=281.6 g.
The balanced equation will tell you that.
C4H10 + O2 ===> CO2 + H2O
C4H10 + 6.5 O2 ===> 4CO2 + 5H2O
The number of mols of CO2 is 4.
Well, according to the law of conservation of mass, the total mass of the reacting atoms must equal the total mass of the final rearranged products produced through the reaction. Assuming that both products are the only products produced, it would constitute the total matter produced, and since each product has a mass of 25 grams each. The total would be 50 grams. Thus the total mass of the reactants also would need to be 50 grams, as no matter is lost in a chemical reaction.
Answer:
Ca3P2
Explanation: find out what 66% of the molar weight of the molecule is and then find out how many moles of Ca that would be by dividing it by the molar weight of Ca
then do the same for P