How many moles of N2 are in a flask with a volume of 0.5 L at a pressure of 400.0 kPa and a temperature of 300.0 K?

0.08moles

Explanation:

Given parameters:

Volume of gas  = 0.5L

Pressure of gas  = 400kPa

Temperature of gas  = 300K

Unknown:

Number of moles of N₂ = ?

Solution:

Applying the ideal gas law which is a combination of the three gas law: Boyle's law, Charles's law and Avogadro's law will solve this problem.

The ideal gas law is stated as;

              PV  = nRT

P is the pressure of the gas

V is the volume of the gas

n is the number of moles

R is the gas constant

T is the temperature of the gas

  We need to convert kPa of the pressure to atm which is a more comfortable unit to work with.

      400kPa will be   = 3.95atm

Input the variables in the equation;

             3.95 x 0.5  = n x 0.082 x 300

                            n  = 0.08moles

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

let that person have a turn to speak : )