# An open flask sitting in a lab fridge looks empty, but it is filled with a mixture of gases called air. If the flask volume is 2.50 L, and the air is at standard temperature and pressure, how many gaseous molecules does the flask contain?

Nov 2, 2016

If we assume that the temperature inside the fridge is $5$ ""^@C, there are $0.219 \cdot m o l \times 6.022 \times {10}^{23} \cdot m o {l}^{-} 1$ of dinitrogen and dioxygen molecules.

#### Explanation:

From the Ideal Gas Law: $n = \frac{P V}{R T}$ $=$ $\frac{1 \cdot a t m \times 5 \cdot L}{0.0821 \cdot L \cdot a t m \cdot {K}^{-} 1 \cdot m o {l}^{-} 1 \times 278 \cdot K}$ $=$ $0.219 \cdot m o l$

And thus we mulitply $0.219 \cdot m o l$ by $\text{Avogadro's number}$.

0.219*molxx6.022xx10^23*mol^-1=??

If the flask were at room temperature, would it contain the same number of molecules?