Question

13. An empty balloon that originally weighs 4.0 g is filled at 2 atm with He gas at0.00 ºC. Once filled, you find the mass of the balloon to be 8.0 g.a. What is the mass of He?b. How many mols of He are in the ballon?c. What is the volume of the filled balloon, in mL?d. What is the density of the He in scientific notation?

Answer 1

1. Mass of He :

Mass of gas = ( Mass of baloon +gas ) - Mass of baloon

= 8.0g -4.0 g

Mass of gas= 4 g

2. Mols of He are in the ballon:

n = m/ M

= 4 g/4g/mol

n of He = 1 mol

3. Volume of the filled balloon, in mL:

PV = nRT

V = nRT /P

= (1 *0.082 *273)/ 2

= 11.93 mL

4. Density of the He in scientific notation:

Density = mass / Volume

= 4 / (11.93/)

= 0.335g/ml