## Orelov 2 years ago 1) A 64 u sample of a compound containing carbon and hydrogen is heated in the presence of oxygen. 144 u of water and 176 u of carbon dioxide are produced. The mass of the molecule is 16 u. Find the empirical and molecular formula. 2) A 17.471 g sample of a compound containing carbon, hydrogen, and oxygen is heated in the presence of oxygen. 10.477 g of water and 25.612 g of carbon dioxide are produced. The molar mass of the molecule is 90.079 g/mol. Find the empirical and molecular formula.

1. Preetha

What have you done so far?

2. Orelov

Honestly nothing because I have no idea what I'm doing....

3. Preetha

First you calculate the moles of C present in CO2 and the moles of H in H2O

4. Orelov

CO2 = 3.9991365500592mol H2O = 7.993214648899199mol Are those right?

5. Orelov

Would I round them?

6. Preetha

Did you do 176 x 10-12 g x 1 mol CO2/44 g

7. Orelov

I came out to 39.7272...

8. Orelov

Wait-- I think I know what I'm doing now, but thank you!

9. Preetha

Ok, in this problem you need to round it to 2 sig figs because you have the number 16 in the problem.