Question

An alloy of iron and carbon was treated with sulfuric acid, in which only the iron reacts.

if a sample of alloy weighing 2.358g gave home hydrogen which causes an explosion and generated 1.0368g of water, what is the percencentage of iron in the alloy? (hint: Hydrogen can react with oxygen in the air and explode)

Answer 1

2H2 + O2 -------------------> 2H2O

4g                                          36g

4g H2 gives -------------------> 36 g water

x g H2 gives -------------------> 1.0368 g water

x = 4 x 1.0368 / 36 = 0.1152 g

H2 mass = 0.1152 g

2Fe + 3H2SO4 ----------------------> Fe2(SO4 )3+ 3H2

111.69 g Fe gives --------------------> 6 g H2

y g Fe gives ----------------------> 0.1152 g H2

y = 111.69 x 0.1152 / 6

y = 2.144 g of Fe

% of Fe = mass of iron x 100 / sample mass

               = 2.144 x 100 / 2.358

               = 90.94 %

percencentage of iron in the alloy = 90.94 %