A balloon is filled with 35.0 L of helium in the morning when the temperature is 35.00 oC.
By noon the temperature has risen to 45.00 oC. What is the new volume of the balloon?

V = 33.9 L

Explanation: We will use Charles Law to solve for the new volume.

Charles Law is expressed in the following formula. Temperatures must be converted in Kelvin.

V1 / T1 = V2 / T2 then derive for V2

V2 = V1 T2 / T1

= 35 L ( 308 K ) / 318 K

= 33.9 L

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%