Question

A typical air sample in the lungs contains oxygen at $100mmHg$, nitrogen at $573mmHg$,n carbon dioxide at $40mmHg$, and water vapor at $47mmHg$. Why are these pressures called partial pressures?

Short answer

These pressures are called partial pressures because this is the pressure these gases have applied if present alone. Now total pressure is the sum of each partial pressure.

Step-by-step solution

Given Information

We have given the pressure of oxygen is $100\mathrm{mmHg}$, the pressure of nitrogen is $573\mathrm{mmHg}$, the pressure of carbon dioxide is $40\mathrm{mmHg}$, and the pressure of water vapor is $47\mathrm{mmHg}$.

Explanation

In a gas, mixture, each gas exerts its partial pressure, which is the pressure it would exert if it were the gas in the container. Dalton's law that the total pressure of a gas mixture is the sum of the partial pressures of the gases in the mixture.

Because this is the pressure these gases have applied if present alone. Now total pressure is the sum of each partial pressure.