1 mole Fe produces 1 mole Cu
<span> molar mass of Fe is 55.8 g / mole
answer: </span><span>55.8g</span>
Given :
A certain compound contains 4.0 g of calcium and 7.1 g of chlorine.
Its relative molecular mass is 111.
To Find :
Its empirical and molecular formulas.
Solution :
Moles of calcium ,
.
Moles of chlorine ,
.
The ratio calcium and chlorine is 1 : 2 .
So , the empirical formula is
.
Now , molecular mass of
is :

So , 
Therefore , the molecular formula is also
.
Hence , this is the required solution .
The average mass of the pennies in the sample is 2.16 g.
We have a set of pennies from which 10.00% have an average mass of 2.15 g and 90.00% have an average mass of 2.156 g. The average mass (am) of the whole set is a weighted average, that considers the mass (m) and the percentage (perc) of each group. We can calculate it using the following expression.

The average mass of the pennies in the sample is 2.16 g.
You can learn more about weighted average here: brainly.com/question/18554478