Solve the following problems on ideal gas equation. Practice makes perfect. 1. A toy balloon filled Analyze
with air has an
internal pressure of
1.25 atm and a
Calculate
volume of 2.50 L.
How many moles of
gas does the balloon
Answers: 1., 0.130 mol, 2.,0,012 mol, 3., 26 220 torr, 4., 1.07 atm
hold? (Assume T =
285 K)
Final Answer

2. A certain quantity of Analyze:
argon gas is under 16
torr pressure at 253K
in a 12 L vessel. How Calculate
many moles of argon
is present?
Final Answer

3. If 11.00 moles of HC1 Analyze:
gas occupies 15.00 L
at 300.0 °C, what is
its pressure in tort? Calculate
Final Answer
Analyze

4. What would be the
pressure of 6.40 g
oxygen gas in a

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 =   = 0.02atm

Volume = 12L

Temperature  = 253K

Using the ideal gas law;

        PV  = nRT

       0.02x12  = n x 0.082 x 253

            n = 0.012mol