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:- 0.0211 moles of air.

Solution:- This problem is based on an ideal gas law equation.

temperature, pressure and volume are given and asked to calculate the moles of the air. Standard pressure is 1.00 atm.

T = 15 + 273 = 288 K

P = 1.00 atm

V = 0.500 L

The ideal gas law equation is, PV = nRT

where R is the universal gas law constant and its value is 0.0821 atm.L per mol per K.

n is the number of moles and its what we are asked to calculate.

For n, the equation is rearranged as:

`n=(PV)/(RT)`

Let's plug in the values and do the calculations:

`n=(1.00atm*0.500L)/((0.0821atm.K)/(mol.K)*288K)`

n = 0.0211 moles

So, there are 0.0211 moles of the air in the bottle.