If the temperature and amount of a gas are held constant, the pressure (P) it exerts is inversely proportional to volume (V). This means that pressure is directly proportional to the inverse of volume, or $1 /$ V. Write this as a proportionality, and then as an equation with $\mathrm{k}^{\prime}$ as the proportionality constant. What are the units of $\mathbf{k}^{\prime}$ if pressure is in atmospheres and volume is in liters?