How many moles in 13 grams of C 2 H6 ? show work

0.43mole

Explanation:

Given parameters:

Mass of C₂H₆   = 13g

Unknown:

Number of moles  = ?

Solution:

To solve this problem we need to first find the molar mass of the given compound.

 Molar mass of C₂H₆ = 2(12) + 6(1)  = 30g/mol

So;

 Number of moles  =  

Number of moles  =    = 0.43mole

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%