# chemistry 101

posted by .

Determine the empirical and molecular formula for a compound made from 54.09% calcium, 2.72% hydrogen, and 43.18% oxygen with a total molar mass of 222.3 g.

• chemistry 101 -

Here is how you do a problem such as this.
Take 100 g sample. That gives you
54.09 g Ca
2.72 g H
43.18 g O.
Convert grams to moles.
54.09/40.1 = about 1.35 moles Ca.
2.72/1 = 2.72 moles H.
43.18/16 = about 2.7 moles O.

Now divide by the smallest number.
1.35/1.25 = 1.00 moles Ca
2.72/1.25 = 2.01 moles H = 2.00 (rounding to whole number)
2.7/1.35 = 2.00 moles O
Empirical formula is CaO2H2
Empirical formula mass is (40.1 + 2*1 + 2*16) = 74
To find the molecular formula, we divide the molar mass by the empirical mass or 222.3/74 = 3.0 (and round to whole number BUT this one comes out whole.). So the molecular formula is
(CaO2H2)3 or we can write it as
Ca3O6H6 which doesn't make any sense to me but this probably is just a problem someone made up.

## Similar Questions

1. ### Chemistry

Please check my answers for the following questions. THANK YOU. 1) The empirical formula of a compound that is 25.9% nitrogen and 74.1% oxygen is.... ANSWER: N2O 2) empirical formula of a compound that consists of 4.80 grams of carbon, …
2. ### chemistry

A 25g sample of a compound composed of Carbon, Hydrogen, and Oxygen was combusted. 55grams of Carbon Dioxide and 30 grams of water were collected. A) What is the empirical formula of the compound?
3. ### chemistry--help

a compound contains 63.15% Carbon, 5.30% hydrogen, 31.55% oxygen. Its molar mass is 152.14 g/mol. determine the empirical and molecular formula. I get the empirical formula to be C8H803 is it right because it is not fitting the molecular …
4. ### Chemistry

I need some help with some of these questions: The action of bacteria on meat and fish produces a poisonous compound called cadaverine. As its name implies, it stinks! It is 58.77 percent carbon, 13.81 percent hydrogen, and 27.40 percent …
5. ### Chemistry

I need some help with some of these questions: The action of bacteria on meat and fish produces a poisonous compound called cadaverine. As its name implies, it stinks! It is 58.77 percent carbon, 13.81 percent hydrogen, and 27.40 percent …
6. ### chemistry

A 12.0g sample of carbohydrate contain 4.50g of carbon, 3.25g of oxygen, and some hydrogen. Determine the percent by mass of hydrogen in your product. Find the empirical formula for a compound that consists of aluminum and chlorine …
7. ### Chemistry

An unknown compound contains only carbon, hydrogen, and oxygen. Combustion analysis of the compound gives mass percents of 31.57% Carbon and 5.30% H. The molar mass is determined by measuring the freezing-point depression of an aqueous …
8. ### Chemistry

I'm confused on how to set up the problem for each question.. 1.) Calculate the empirical formula of a compound if a 6.21 g sample contains 1.67g of cerium and the remainder iodine 2.) An unknown compound contains 85.64% carbon with …
9. ### Chemistry Really Confused!!

'm confused on how to set up the problem for each question.. 1.) Calculate the empirical formula of a compound if a 6.21 g sample contains 1.67g of cerium and the remainder iodine 2.) An unknown compound contains 85.64% carbon with …
10. ### CHEMISTRY

A compound which contains hydrogen, oxygen, carbon only has molar mass of about 85 g/mol. When 0.43 g of the compound is burned in excess of oxyfen, 1.10 g of CO2 and 0.45 g of H2O are formed. Find the molecular formula and the empirical …

More Similar Questions