the compound XYZ (little 3) has a molar mass of 100.09 g and a percent composition (by mass) of 40.04% X. 12.00%Y, and 47.96% Z. What is the formula of the compound?

Calcuim carbonate (CaCO3)

Explanation:

To find the chemical formula of this unknown compound, we will use their percentage composition individually.

Total molar mass of the compound = 100.09 g

Percentage of mass of element X=40.04

= 40.04/100 x 100.09

=40.08g

Percentage of mass of element Y=12.00

= 12.00/100 x 100.09

=12.01 g

Percentage of mass of element Z=47.96

= 47.96/100 x 100.09

=48.00 g

As from the formula of the compound XYZ (little 3) we can see that is in 3 in numbers so we will divide 48.00 by 3, 48/3 to get 16. so mass of Z is 16 grams.

Now just look at the periodic table and match the mass of these elements there.

We can see that mass of 40.08 is for calcuim (Ca), mass of 12.01 is of carbon (C), mass of 16.00 is of Oxygen (O). So, we can say that element X is calcium, Y is carbon and Z is Oxygen. replacing their symbols in the formula.

XYZ (little 3) = CaCO3

So the compound is Calcium carbonate.