Question: 1.How many moles of O2 are produced in the decomposition of 54 g of water in the following reaction?

0.50 mol
2.0 mol
1.5 mol
2.5 mol

2.Zinc reacts with hydrochloric acid according to the equation:

The moles of H2 produced from the reaction of 2 mol of HCl is:
1 mol
2 mol
22.4 mol
44.8 mol

3.Acetylene, C2H2, burns completely in oxygen, O2, to produce carbon dioxide, CO2, and water, H2O, according to:

If 8.3 mol of C2H2 are completely burned in excess oxygen, the number of moles of CO2 produced are:
4.00 mol
8.33 mol
4.15 mol
16.6 mol  Edit

Answer: Ans1
1 mol H2O= 18 gm
that means when 18 gm of H2O discompose it gives 16 gm O2
54 gm of H2O discompose it gives 16*54/18=48 gm

32 gm O2 means 1 mol
48 gm O2 means 1.5 mol

Ans 2
Zn + 2 HCl = ZnCl2 + H2
2 mol of HCl will give 1 mol of H2

Ans 3
2C2H2 +5O2 -> 4CO2 + 2H2O
From the balanced chemical equation it is clear that,
In presence of excess oxygen, 2 mol of C2H2 burns to give 4 mol of CO2
then 8.3 mol of C2H2 burns to give 4*8.3/2= 16.6 mol of CO2  Edit