Question

Solve the following problems on ideal gas equation. Practice makes perfect.

Answer 1

Answer:

0.012mol

Explanation:

1.

Given parameters:

Pressure in the balloon  = 1.25atm

Volume of the balloon  = 2.5L

Unknown:

Number of moles  = ?

Solution:

We are going to used the combined gas law to solve this problem.

  PV = nRT

P is the pressure

V is the volume

n is the number of moles

R is the gas constant  = 0.082atmdm³mol⁻¹K⁻¹

 Insert the parameters and solve;

    1.25 x 2.5  = n x 0.082 x 285

       n  = 0.13mol

The number of moles is 0.13mol

2.

Given parameters:

Pressure  = 16torr;

   to atm is ;

                 760torr  = 1atm

                  16torr = $\frac{16}{760}$   = 0.02atm

Volume = 12L

Temperature  = 253K

Using the ideal gas law;

        PV  = nRT

       0.02x12  = n x 0.082 x 253

            n = 0.012mol