How many moles of air are there in a 125 mL Erlenmeyer flask if the pressure is 755 mm Hg and the temperature is 20.0°C?

To Find :

How many moles of air are there in a 125 mL Erlenmeyer flask if the pressure is 755  mm Hg and the temperature is 20.0°C .

Solution :

Since, air contains different gas in different proportion.

Its average molar mass is considered to be 29 gram/mol .

Now, we know by ideal gas equation :

Here, R is ideal gas equation,

Putting all given values we get :

Hence, this is the required solution.

1. they vary with a higher number because boiling is way hotter than melting