6 How many moles are in a 321 g sample of magnesium? F 13.2 mol Mg
G 13.4 mol Mg
H 13.6 mol Mg
J 13.8 mol Mg

13.4mol of Mg

Explanation:

Given parameters:

Mass of magnesium = 321g

Unknown:

Number of moles  = ?

Solution:

The number of moles of a substance is given as;

  Number of moles  =  

 Molar mass of Mg = 24g/mol

 Insert the parameters and solve;

        Number of moles  =   = 13.4mol of Mg

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer