posted by Anonymous .
If 36 grams of water yield 4.0 grams of hydrogen gas after a chemical reaction, how many kilograms of hydrogen gas will you obtain from 4.35 x 10^4 milligrams of water?
36 grams of H2O is equivalent to 2 mole of H2O, and 4.0 grams of H2 is equivalent to 2 mole of H2.
So, the reactant to product mole ratio is 1:1.
Convert mg to g and solve for the number of moles.
4.135 x 10^4 mg*(10^-3 g/1 mg) = H2O in g
H2O in g *(1 mole/18.00g) = moles of H2O
moles of H2O=moles of H2
moles of H2*(2 g/1 mole of H2)= mass of H2 in g
mass of H2 in g*(10^-3 kg/1g)= mass of H2 in kg