Question

what is the total mass of water formed when 8 grams of hydrogen completely reacts with 64 grams oxygen

Answer 1

Question: Given the balanced equation representing a reaction:

2H2 + O2 ==>2H2O

What is the total mass of water formed when 8 grams of hydrogen reacts completely with 64 grams of oxygen?

(1) 18 g (3) 56 g

(2) 36 g (4) 72 g

Answer:

"72 gram" is the total mass of water formed when 8 grams of hydrogen reacts completely with 64 grams of oxygen

Explanation:

We will do stoichiometry in this kind of problem:

$8g of H_2O\times(\frac{1molO_2}{2.0g H_2})(\frac{2 mol H_2O}{2mol H_2})(\frac{18g H_2O}{1molH_2O}) = 72g H_2O$

$64 g O_2 \times (\frac{1molO_2}{32g O_2})(\frac{2 mol H_2O}{1mol O_2})(\frac{16gH_2O}{1 mol H_2O}) = 72g H_2O$

Therefore, the total mass of water formed is 72 g.