Is that 0.06120 g sample;
0.1601 g CO2 and 0.05243 g H2O? I may not be reading those funny symbols correctly.
Hey, can someone help me with this?
A compound containing only C, H and O was subjected to combustion analysis. A sample of 6.120×10^-2 g produced 1.601×10^-1 g of CO2 and 5.243×10^-2 g of H2O. Determine the empirical formula of the compound and enter the appropriate subscript after each element.
C H O
Then they ask "If the molar mass of the compound is 252.354 g/mol, determine the molecular formula of the compound and enter the appropriate subscript after each element."
C H O
4 answers
Sorry, it's 0.06120 g produced 0.1601 g of CO2 and 0.05243 g of H2O
In order to find g oxygen you need to first convert CO2 to C and H2O to H.
g C = 0.1601 x (12.01/44) = ?
g H = 0.05243 x (2*1/18) - ?
g O = 0.06120 - g C - g H = ?
mols C = g C/12.01 = ?
mols H = g H/1 = ?
mols O = g O/16 = ?
Now find the ratio of these three elements to each other with the smallest number being no less than 1. The easy way to do that is to divide the smallest number by itself (that's the easy way to make it 1.00000); then divide the other numbers by the same small number. Round to whole numbers.
g C = 0.1601 x (12.01/44) = ?
g H = 0.05243 x (2*1/18) - ?
g O = 0.06120 - g C - g H = ?
mols C = g C/12.01 = ?
mols H = g H/1 = ?
mols O = g O/16 = ?
Now find the ratio of these three elements to each other with the smallest number being no less than 1. The easy way to do that is to divide the smallest number by itself (that's the easy way to make it 1.00000); then divide the other numbers by the same small number. Round to whole numbers.
So I've done as you said and have come up with the following:
C (g) = 0.0437g
H (g) = 0.00583g
O (g) = 0.01167g
C(mol)=0.00364mol
H(mol)=0.00578mol
O(mol)=0.000729
I then divide for the ratio (Mm=m/n) and get 12 for C, 1 for H, and 16 for O, making the formula:
C12HO16, but it comes up as incorrect. Also, I was wondering where the 44 and 18 came from in your explanation:
g C = 0.1601 x (12.01/44) = ?
g H = 0.05243 x (2*1/18) - ?
Where am I going wrong here?
C (g) = 0.0437g
H (g) = 0.00583g
O (g) = 0.01167g
C(mol)=0.00364mol
H(mol)=0.00578mol
O(mol)=0.000729
I then divide for the ratio (Mm=m/n) and get 12 for C, 1 for H, and 16 for O, making the formula:
C12HO16, but it comes up as incorrect. Also, I was wondering where the 44 and 18 came from in your explanation:
g C = 0.1601 x (12.01/44) = ?
g H = 0.05243 x (2*1/18) - ?
Where am I going wrong here?