have you tried it yourself? you should, cause stoichiometry apparently requires lots of practice
hint: write your stoichiometric equations first
3 is slightly more challenging than the rest, so what you could do is to write the equation of combustion first
CxHy + (y/4 +x) O2 --> y/2 H2O + xCO2
then solve for x and y, since you do know the amount of water produced
A single flow'r he sent me, since we met./All tenderly his messenger he chose;
Deep-hearted, pure, with scented dew still wet - One perfect rose.
I knew the language of the floweret;/'My fragile leaves,' it said, 'his heart enclose.'
Love long has taken for his amulet/One perfect rose.
Why is it no one ever sent me yet/One perfect limousine, do you suppose?
Ah no, it's always just my luck to get/One perfect rose.