Question

An empty water bottle is full of air at 15°C and standard pressure. The volume of the bottle is 0.500 liter. How many moles of air are in the bottle?

Answer 1

Answer:  0.02 moles

Explanation: Using ideal gas equation:  

$PV=nRT$

$n=\frac{PV}{RT}$

P = pressure = standard pressure= 1 atm

V = volume = 0.500L

n = no of moles = ?

R = gas constant =0.0821 Latm\molK

T= temperature = $15^0C$ = (15+273)K= 288K

$n=\frac{1\times 0.500}{0.0821\times 288}=0.02moles$