(a) After the label fell off a bottle containing a clear liquid believed to be benzene, a chemist measured the density of the liquid to verify its identity. A $25.0-\mathrm{mL}$ portion of the liquid had a mass of 21.95 g. A chemistry handbook lists the density of benzene at $15^{\circ} \mathrm{C}$ as $0.8787 \mathrm{~g} / \mathrm{mL}$. Is the calculated density in agreement with the tabulated value? (b) An experiment requires $15.0 \mathrm{~g}$ of cyclohexane, whose density at $25^{\circ} \mathrm{C}$ is $0.7781 \mathrm{~g} / \mathrm{mL}$. What volume of cyclohexane should be used?
(c) A spherical ball of lead has a diameter of $5.0 \mathrm{~cm}$. What is the mass of the sphere if lead has a density of $11.34 \mathrm{~g} / \mathrm{cm}^{3} ?$ (The volume of a sphere is $(4 / 3) \pi r^{3},$ where $r$ is the radius.)