Chapter 2, Problem 62A

Interpretation Introduction

Interpretation: The mass of water formed in the explosion of ammonium nitrate needs to be determined.

Concept Introduction: According to the law of conservation of mass, in any chemical reaction, no mass can be created or destroyed. Thus, the total mass of reactants is equal to the total mass of products formed.

Answer to Problem 62A

18 g

Explanation of Solution

According to the question, ammonium nitrate $\left({\text{NH}}_{\text{4}}{\text{NO}}_{\text{3}}\right)$ explodes to form nitrogen, oxygen, and water.

The mass of ammonium nitrate is given 40 g and that of nitrogen and oxygen is given 14 g and 8 g respectively. Here, the mass of water is not given and needs to be determined.

Total mass of the product formed is 40 g, thus, as per the law of conservation of mass, the total mass of reactant must be 40 g. This can be calculated as follows:

  $m_{\text{reactants}}=m_{{\text{O}}_{\text{2}}}+m_{{\text{N}}_{\text{2}}}+m_{{\text{H}}_{\text{2}}\text{O}}$

Substituting the values,

  $40\text{ g}=8\text{ g}+14\text{ g}+m_{{\text{H}}_{\text{2}}\text{O}}$

Rearranging,

  $\begin{array}{c}{m}_{{\text{H}}_{\text{2}}\text{O}}=40\text{ g}-8\text{ g}-14\text{ g}\\ \text{=18 g}\end{array}$

Conclusion

Thus, the mass of water formed is 18 g.