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

the answer is c. nacl