Question

2. In which of the following reactions do four total molecules of reactants produce two total molecules of products?
(Points : 3)
N2 + 3H2 2NH3

SnO2 + 2H2 Sn + 2H2O

2H2S + 3O2 2SO2 + 2H2O

2SO2 + O2 2SO3

Answer 1

add the coefficients on each side of the equation

for example, the third one

2H2S + 3O2 ----> 2SO2 + 2H2O

Reactants:
2 Hydrogen Sulfide H2S
3 Oxygen O2
---------------------
5 Total molecules

Products:
2 Sulfur Dioxide SO2
2 Water H2O
---------------------
4 Total Molecules

This reaction has 5 molecules reacting and 4 molecules as the Product. Do the same for the other reactions to find the one with 4 Reacting molecules and 2 molecules as products.