Find the number of moles in 85 g KCl.
A.3.3 mol KCl
B.1.1 mol KCl
C.11 mol KCl
D.2.5 mol KCl

Question

Find the number of moles in 85 g KCl. 
A.3.3 mol KCl
B.1.1 mol KCl
C.11 mol KCl
D.2.5 mol KCl

anonymous · Answer

1 mole of KCl has 39.10g for K and 35.45g for Cl
Add these together: 74.55g
Now 85g of KCl x 1 mol KCl / 74.55g = 1.1 mol

Answer is B

anonymous · Answer

Well I took K as 38 and Cl as 34...
So the relative molecular mass is..
$$R.m.m={(38*1)+(34*1)}$$$$=38+34$$$$=72$$So molar mass = 72gmol^-1
We could apply this in the formula$$n=\frac{m}{M}$$Where n = number of moles , m = molar mass of substance and M = mass of substance..So$$n=\frac{85g}{72gmol^{-1}}$$$$n=1.18mol$$$$n=1.1mol$$..  :D