Question

What mass of water will be obtained if 1 gram of hydrogen is burned in 10 grams of oxygen

Answer 1

Here is how you crack it up!

write the balanced chemical equation for the reaction:

4H + O2 ⇄ 2H2O, thus 4moles of H reacted with 1mole of O to produce 2moles of H2O.

change the mass of the reactant Oxygen into moles; thus 0.625mol

compare the mole ratios of oxygen to that of water;

4mol(O)   :     2mole(H2O)

0.625mol :    X

cross multiply to obtain 0.3125mol of H2O

change the moles of H2O to its mass using the formula

No of moles = mass/ molar mass

Data

mass of H2O, ?

number of moles of H2O, 0.3125mole

molar mass of H2O, 18g/mol

∴mass of H2O = 5.6g

Hope that was helpful.