Question

Q. 20. When 200 gm of H2 and 200 gm of O, is reacted in a closed vessel, calculate mass of
water formed and mass of reactant left.
Q. 21. Find the volume of CO2 evolved when 200 gm of CaCO3 (90% pure) undergoes thermal
decomposition​

Answer 1

Answer:

Q20) 450 g water formed

150 g h2 left

Explanation:

O2 is your limiting reagent

calculate no of moles of o2 = 200/16 = 12.5 mol

now write the equation

2H2 + O2 -> 2h2o

2 vol. 1 vol. 2 vol

2 mol. 1 mol. 2 mol

for every mol of o2 two moles of h2o is formed

therefore for 12.5 mol o2 reacting 25 mol h2o must be formed

25 x 18 (MM of water) = 450g

Hydrogen left -

initially 200g i.e. 100 moles of h2 present

25 moles were used up during reaction

therefore 75 moles i.e 150g is left