.Pheromones are substances secreted by females of many insect species to attract mates. Typically, $1 \times 10^{-8} \mathrm{~g}$ of a pheromone is sufficient to reach all targeted males within a radius of 0.50 mi . Calculate the density of the pheromone (in grams per liter) in a cylindrical air space having a radius of 0.50 mi and a height of 40 ft . (Volume of a cylinder of radius $r$ and height $h$ is $\pi r^2 h$.)