1. How many moles of gas are in a sample of gas at a pressure of 1.2 atm, a

volume of 21 liters, and a temperature of 145 °C? (Hint: K = °C + 273)

1.36moles

Explanation:

Given parameters:

Pressure of gas = 1.2atm

Volume of gas = 21liters

Temperature of gas = 145°C, in Kelvin gives 273 + 145 = 418K

Unknown:

Number of moles of the gas = ?

Solution:

To solve this problem, we are going to use the ideal gas equation which combines the three gas laws; Boyle's law, Charles's law and Avogadro's law.

Mathematically, it is given as;

PV = nRT

where;

P is the pressure of gas

V is the volume of gas

n is the number of moles

R is the gas constant = 0.082

T is the temperature

Substitute the values and solve for n;

1.2 x 21 = n x 0.082 x 418

solving for n;

n = 1.36moles