Question

4 g oh hydrogen reacts with 20 g of oxygen to form water. the mass of water formed is?

Answer 1

From the balanced chemical reaction of water , we know that:

2H₂ + O₂ --------> 2H₂O
​ (4g) (32g) (36g)

i.e.

32g of oxygen gives 36 g of H₂O
​20g of oxygen = (36/32)$\times$ 20
= 22.5 g of H₂O.