The combustion of a compound which contains only C and H yields 2.58 g of CO2 and 0.53 g of H2O. What is the empirical formula of the compound?
Molar mass of CO2= 44.01
Molar mass of H20= 18.01
2.58g/44.01=0.586 mol CO2
.53g/18.01=.0294 mol H2O
I Don't know where I went wrong?
You've gotten the moles of CO2 and H20, but now you must find the only the moles of Carbon and Hydrogen.
Originally, the compound that was combusted only contained C and H. Therefore, all the C in the compound went into CO2 and all the H went into H2O.
To find the moles of C in 0.0586 moles of CO2 (it's 0.0586 instead of 0.586 like you said above), you must multiply (via dimensional analysis) by the fraction (1 mole of C) / (1 mole of CO2) which is saying that for every mole of CO2, there is one mole of C. You'd get the same answer, 0.586 mole C.
To find the moles of H in 0.0294 moles of H2O, you follow a similar process. Your dimensional analysis factor this time is (2 mole H) / (1 mole H2O) which shows that for every mole of H2O there are two moles of H.
Once you've got your moles of C and H, take the lowest number of moles and divide each product by that number. In this case, you should find that the resulting quotients each are about equal to 1 which would make the empirical formula CH.
Let me know if you get these results.
To find the empirical formula of the compound, you need to determine the ratio of the elements present in the compound. Let's start by finding the moles of carbon (C) and hydrogen (H) in the given amounts of CO2 and H2O.
First, we calculate the moles of carbon dioxide (CO2):
Moles of CO2 = mass of CO2 / molar mass of CO2
Moles of CO2 = 2.58 g / 44.01 g/mol ≈ 0.0586 mol
Next, we calculate the moles of water (H2O):
Moles of H2O = mass of H2O / molar mass of H2O
Moles of H2O = 0.53 g / 18.01 g/mol ≈ 0.0294 mol
Now, we need to determine the ratio of carbon to hydrogen in the compound. To do this, we'll divide the moles of carbon and hydrogen by the smaller value.
Moles of C / moles of H = 0.0586 mol / 0.0294 mol ≈ 2
From this calculation, we determine that the ratio of carbon to hydrogen in the compound is approximately 2:1.
The empirical formula of the compound is CH2.