# A canister contains 25 kPa of CO_2, 7.50 kPa of N_2, and 52.5 kPa of O_2. What is the total pressure within the canister?

Aug 7, 2017

This is simply the sum of the individual partial pressures...........and you can do the sum in your head.......to get $85 \cdot k P a$.

#### Explanation:

And this follows Dalton's law of partial pressures.....$\text{in a gaseous}$
$\text{mixture the partial pressure exerted by each gas is the same }$
$\text{as the pressure it would exert if it alone occupied the container.}$

$\text{The total pressure is the sum of the individual partial pressures.}$

This is an experimental gas law that has copious experimental support.

ANd thus ${P}_{\text{Total}} = {P}_{C {O}_{2}} + {P}_{{N}_{2}} + {P}_{{O}_{2}}$

$= \left\{25 + 7.5 + 52.5\right\} \cdot k P a$

$= 85 \cdot k P a$

I think you can see from where the examiner pulled those figures.