# chemistry

posted by .

a compound with the molecular weight of 276 grams was determined to be 39.10% carbon, 8.77% hydrogen, and 52.13% oxygen. what is the empiricial formula and the molecular formula for the compound? i do not know where to start!

i worked it out and i got 276/100=2.76 do i round it up to 3? SO THE MOLECULAR FORMULA IS 3(ch30)? then i divided 39.10/12.01=3.25/3.25 =1 and the same for oxygen becaseu their answers were both the smallest. for hydrogen i divided 8.77/1.008=8.70/3.25=2.67 do you round up to 3? so the EMPIRICAL FORMULA is CH30 because you round up? or do i keep it as CH20? THANKS SO MUCH!!!!

• chemistry -

You did great. I would not round 2.67 to 3. I would look for a multiplier where all would be whole numbers; for example, if we multiply by 3 we get C = 3, H = 8.01 (which we round to 8.0), O = 3 so the empirical formula is C3H8O3. That makes the empirical formula mass of 36 + 8 + 48 = 92.
Then 276/92 = 3 so the molecular formula is
(C3H8O3)3 = C9H27O9. Check that to make sure it adds to 276. Generally we round if the number is close to a whole number (2.9 would round to 3 and 2.1 would round to 2.0. Generally, numbers close to 0.25, 0.5 and 0.75 can be multiplied to obtain whole numbers. 4*0.25 = 1. etc.

## Similar Questions

1. ### A.P Chemistry

Three volatile compounds X,Y, and Z each contain elements Q. The precent by weight of element Q in each compound was determined. Some of the data obtained are given below Percent by weight Molecular Compound of Element Q Weight X 64.8% …
2. ### 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, …
3. ### chemistry

a compound with the molecular weight of 276 grams was determined to be 39.10% carbon, 8.77% hydrogen, and 52.13% oxygen. what is the empiricial formula and the molecular formula for the compound?
4. ### 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?
5. ### Chemistry

The molecular formula of a compound containg only carbon and hydrogen is to be determined. When a sample of the compound is burned on oxygen gas, 7.2 grams of water and 7.2 liters of carbon dioxide gas are produced(measured at STP). …
6. ### Chemistry

A certain compound contains carbon, hydrogen , and oxygen. When 1.00 grams of this compound are burned in oxygen gas 1.47 grams of CO2 and 0.600 grams of water are formed. When 2.75 grams of the compound are dissolved in 10.0 grams …
7. ### Chemistry

A certain compound contains carbon, hydrogen , and oxygen. When 1.00 grams of this compound are burned in oxygen gas 1.47 grams of CO2 and 0.600 grams of water are formed. When 2.75 grams of the compound are dissolved in 10.0 grams …
8. ### A.P. Chemistry

Three volatile compounds X,Y, and Z each contain elements Q. The precent by weight of element Q in each compound was determined. Some of the data obtained are given below Percent by weight Molecular Compound of Element Q Weight X 64.8% …
9. ### 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 …
10. ### 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 …

More Similar Questions