Chapter 3, Problem 51A

Interpretation Introduction

Interpretation:

The mass of the reactants needs to be determined.

Concept introduction:

According to law of conservation of mass, total mass of reactant and product in a chemical reaction remains the same before and after the completion of the reaction.

Answer to Problem 51A

47 g.

Explanation of Solution

The mass of the sample of X and Y to form compound XY₂ is 13 g and 34 g respectively.

According to the law of conservation of mass, the total mass of a substance remains the same before and after the reaction. The mass of product formed after the reaction of X and Y will be sum of masses of X and Y as follows:

$\begin{array}{l}{m}_{product}=m_X+m_Y\\ =13+34=\text{47 g}\end{array}$

Also, the mass of product formed is equal to the mass of reactants therefore,

$m_{\text{reactant}}=m_{product}=47\text{ g}$

Conclusion

The mass of reactants is 47 g.