Chapter 15, Problem 81CP

(a)

Interpretation Introduction

Interpretation:A concentrated nitric acid solution is used to dissolve copper (II) sulphide

  $\text{CuS}\left(\text{s}\right){\text{ + HNO}}_{\text{3}}\left(\text{aq}\right)\to {\text{CuSO}}_{\text{4}}\left(\text{aq}\right)\text{ + NO}\left(\text{g}\right){\text{ + H}}_{\text{2}}\text{O}\left(\text{l}\right)$

To write the balanced equation

Concept Introduction: The balanced chemical reaction is the equation in which number of constituents are same on both sides of the reaction arrow. It is in accordance with law of conservation of mass.

(b)

Interpretation Introduction

Interpretation: A concentrated nitric acid solution is used to dissolve copper (II) sulphide

  $\text{CuS}\left(\text{s}\right){\text{ + HNO}}_{\text{3}}\left(\text{aq}\right)\to {\text{CuSO}}_{\text{4}}\left(\text{aq}\right)\text{ + NO}\left(\text{g}\right){\text{ + H}}_{\text{2}}\text{O}\left(\text{l}\right)$

To find how many millilitres of a 16.0 M HNO₃solution are needed to dissolve 24.8 g of CuS.

Concept Introduction:The number of moles of substance can be calculated from mass and molar mass as follows:

  $\text{Moles = }\frac{\text{mass }}{\text{molar mass}}$

Also, molarity of solution is number of moles of solute in 1 L of the solution. It is mathematically represented as follows:

  $M=\frac{n}{V\left(L\right)}$

Here, n is number of moles of solute and V is volume of solution.