Question

In a chemical reaction, Hydrogen consist 4g, Oxygen consist 12g Product is formed water Calculate the amount of water in g

Answer 1

2H2 + O2 → 2H20
number of moles of hydrogen=4g/the molar mass of H2=4/2=2moles
number of moles of oxygen=12/32=0.375moles
now we know that for every 1 mole of O2 we have 2 moles of H2O.

so we multiply 0.375 by 2 to get the amount of moles of water we will have.

0.375 x 2 =0.75 moles of water

so we need to work out the mass of 0.75 moles of water. the molar mass of water is 16 (O) + 2 (H2) = 18g/mol

then we do 18 x 0.755 to get 13.5g of water
the mass of water getting is 13.5g