100 cm3 of hydrogen is mixed with 25 cm3 of oxygen at a temperature of 150qC. The gases react as shown in the equation below. 2H2(g)+ O2(g) o 2H2O(g) The total volume of gas present at the end of the reaction is A 50 cm3 B 100 cm3 C 125 cm3 D 150 cm

B 100 cm3

Explanation:

The balanced equation is given as;

2H2(g)+ O2(g) --> 2H2O(g)

From the reaction stochiometry, 2 cm3 of H2 would react with 1 cm3 of O2 to form 2 cm3 of H2O

Before Reaction --> 100cm3 of H2,   25cm3 of O2,  0cm3 of H2O

During Reaction --> 50cm3 of H2,    25cm3 of O2,   50cm3 of H2O

(Oxygen is sed uup in the reaction)

After Reaction   --> 50cm3 of H2,    0cm3 of O2,     50cm3 of H2O

Total volume left = Unreacted H2 (50cm3)  +  50cm3 of H2O formed

Total Volume left = 50  + 50  =  100cm3