Question

Find the number of moles and the number of molecules in one cubic meter of air at 1 atmospheric pressure and 0C.

Answer 1

Answer:

The number of moles of the air is 4.464 x 10⁻⁴ mole

The number of molecules is  2.688 x 10²⁰ molecules

Explanation:

Given;

pressure of the air, P = 1 atm

volume of the air, V = 1 m³

temperature of the air, T = 0° C = 273 K

The number of moles of the air is calculated as;

PV = nRT

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

where;

n is the number of moles

R is ideal gas constant = 8.2057m³atm/mol.k

$n = \frac{1atm \ \times \ 1m^3}{(8.2057 \ m^3 atm/mol.K)(273 \ K)} = 4.464 \ \times 10^{-4} \ mol.$

The number of molecules is calculated as follows;

1 mole  ---------------------> 6.022 x 10²³ molecules

4.464 x 10⁻⁴ mole ----------> ?

= (4.464 x 10⁻⁴) (6.022 x 10²³ molecules)

= 2.688 x 10²⁰ molecules of air.