Question

When molybdate (MoO3) and Zinc (Zn) are heated together they react in this equation:

Answer 1

Answer: The mole ratio of Zn to ZnO is 3: 3.

Explanation:

According to law of conservation of mass, mass can be neither be created nor be destroyed. The mass on reactant side must be equal to the mass on product side. Thus the atoms of each element on both side of the reaction must be same.

The balanced chemical reaction is:

$3Zn+2MoO_3\rightarrow Mo_2O_3+3ZnO$

Here 3 moles of Zn combine with 2 moles of $MoO_3$ to give 1 mole of $Mo_2O_3$ and 3 moles of $ZnO$. Thus the mole ratio of Zn to ZnO is 3: 3.