Question

Write a balanced chemical equation when

Phosphorus burns with oxygen to form phophorus pentoxide

Answer 1

Step 1: Given phosphorus burns in oxygen to form phosphorus pentoxide. So, the reactants are Phosphorus ($P_4$) and oxygen ($O_2$) and the product is phosphorus pentoxide ($P_2{O}_5$). Then the unbalanced chemical equation is

$P_4+O_2⟶P_2{O}_5$

Step 2: In the equation, the number of phosphorus atoms in the reactants and products are 4 and 2 respectively. Also, the number of oxygen atoms in the reactants and products are 2 and 5 respectively. So, multiply $O_2$ by 5 and $P_2{O}_5$ by 2. Then the number of atoms in the reactants and products become the same.

Step 3: Hence, the balanced chemical equation is

$P_4+5O_2⟶2P_2{O}_5$