A balloon is filled with 5000.00 milligrams of helium gas at STP. What is the volume of the
balloon? (Use the ideal gas law and gfm for a start. (Molar volume of a gas))

The answer to your question is       V = 30.03 L

Explanation:

Data

mass of Helium = 5000 mg

Volume = ?

Temperature = 20°C

Pressure = 1 atm

constant of ideal gas = 0.082 atmL/mol°K

Process

1.- Calculate the moles of Helium

Atomic mass = 4 g

5000 mg = 5 g

                         4g 1 mol

                         5g  x

                           x = (5 x 1)/4

                           x = 5/4 moles

2.- Convert temperature to °K

Temperature = 20 + 273 = 293°K

3.- Use the ideal gas law to find the volume

     PV = nRT

-Solve for V

     V = nRT / P

-Substitution

     V = (5/4)(0.082)(293) / 1

-Simplification

     V = 30.03 L