A tabulation of data lists the following equation for calculating the
densities \((d)\) of solutions of naphthalene in benzene at \(30^{\circ}
\mathrm{C}\) as a function of the mass percent of naphthalene.
$$d\left(\mathrm{g} / \mathrm{cm}^{3}\right)=\frac{1}{1.153-1.82 \times
10^{-3}(\% \mathrm{N})+1.08 \times 10^{-6}(\% \mathrm{N})^{2}}$$
Use the equation above to calculate (a) the density of pure benzene at
\(30^{\circ} \mathrm{C} ;\) (b) the density of pure naphthalene at \(30^{\circ}
\mathrm{C} ;\) (c) the density of solution at \(30^{\circ} \mathrm{C}\) that is
1.15\% naphthalene; (d) the mass percent of naphthalene in a solution that has
a density of \(0.952 \mathrm{g} / \mathrm{cm}^{3}\) at \(30^{\circ} \mathrm{C}
.[\text { Hint: For }(\mathrm{d}),\) you need to use the quadratic formula. See
Section A-3 of Appendix A.]