Question

If the hydrogen used was produced by the reaction of carbon with steam, how many kilograms of carbon would have been needed to produce enough hydrogen to fill the dirigible at 25 ∘C and 741 mm Hg pressure? C(s)+H2O(g)→CO(g)+H2(g)

How many milliliters of O2 gas at 25 ∘C and 1.00 atm pressure are obtained by the thermal decomposition of 0.240 g of KMnO4? The balanced equation for the reaction is 2KMnO4(s)→K2MnO4(s)+MnO2(s)+O2(g).

Answer 1

2KMnO₄(s) → K₂MnO₄(s) + MnO₂(s) + O₂(g)

moles of KMnO₄ = mass/molarmass

                           = 0.240/158.034

                           = 0.00152 moles

From the balanced chemical equation:

2 moles of KMnO₄ gives ----> 1 mole of O2

0.00152 moles of KMnO₄ gives ----> 1*0.00152/2

                                                    = 0.00076 moles of O2

According to ideal gas equation:

PV = nRT

1.00*V = 0.00076*0.0821*298

V = 0.0186 L

   = 18.6 mL

Volume of O2 gas = 18.6 mL

Some data is missing for the First problem.