Question

Helium has a density of 1.79 x 10-4 g/mL at standard temperature and pressure. A balloon has a volume of 6.3 liters. Calculate the mass of helium that it would take to fill the balloon. Be sure to follow significant figure rules when calculating the answer.

Answer 1

 The mass    of  Helium that it would take  to fill the balloon is  1.1277 grams  of helium

calculation

mass  = density  x volume

Density  = 1.79  x 10 ⁻⁴ g/ml

Volume  = 6.3 L

• convert  volume  into ml to make  the unit uniform

 that is  1 L = 1000 ml

             6.3 L =? L

by cross  multiplication

= ( 6.3 L x 1000 ml) / 1 L = 6300 ml

mass  is therefore  = 1.79 x 10⁻⁴ g/ml x 6300  ml= 1.1277 grams

Answer 2

Density = 1.79x10⁻⁴ g/mL

1  L = 1000 mL

6.3 L = ?  

6.3 x 1000 => 6300 mL

Mass of helium:

m = D x V  

Therefore:

m = ( 1.79x10⁻⁴ ) x  6300

m = 1.1277 g of helium