an organic compound contains C , H and O. in one combustion analysis, 10.71 g of this compound yields 6.41 g of H2O and 15.72 g of CO2. Calculate the number of carbon atoms in this organic compound if the molar mass of the compound is 146 g/mol
Find the formula as follows:
g C = g CO2 x atomic mass C/molar mass CO2 = approx 4
g H = g H2O x 2*atomic mass H/molar mass H2O = approx 0.7
g O = g compound - g C - g H = approx 6
mols C = g C/atomic mass C = approx 0.35
mols H = g H/atomic mass H = approx 0.7
mols O = g O/atomic mass O = approx 0.35 so the ratio is
CH2O for the empirical formula and 30 is the empirical mass.
molecular formula is 146/30 = 4.9 so round to 5 and the molecular formula is C5H10O5. My assumption is that the 146 is an approx molar mass but it is 150 from the molecular formula.
mols compound is 10.71/150 = x
C atoms = x*6.02E23*5
To determine the number of carbon atoms in the organic compound, we need to use the given information and apply the concept of stoichiometry.
First, we calculate the number of moles of water (H2O) produced:
Molar mass of H2O = 2(g/mol for hydrogen) + 16(g/mol for oxygen) = 18 g/mol
Number of moles of H2O = mass of H2O / molar mass of H2O = 6.41 g / 18 g/mol
Number of moles of H2O = 0.356 mol
Next, we calculate the number of moles of carbon dioxide (CO2) produced:
Molar mass of CO2 = 12(g/mol for carbon) + 2 * 16(g/mol for oxygen) = 44 g/mol
Number of moles of CO2 = mass of CO2 / molar mass of CO2 = 15.72 g / 44 g/mol
Number of moles of CO2 = 0.357 mol
Since the organic compound contains both carbon atoms and the ratio between the moles of water and carbon dioxide is 1:1, it implies that 1 mol of carbon is present in the compound.
To calculate the number of carbon atoms, we need to determine the number of moles of the organic compound.
Total moles of the compound = moles of H2O (0.356 mol) = moles of CO2 (0.357 mol) = 0.356 mol
Now, we can calculate the number of carbon atoms in the organic compound:
Number of moles of carbon = Total moles of the compound = 0.356 mol
To convert the number of moles of carbon into the number of carbon atoms, we use Avogadro's number, which states that 1 mole of any substance contains 6.022 x 10^23 particles (atoms, molecules, etc.).
Number of carbon atoms = Number of moles of carbon * Avogadro's number
Number of carbon atoms = 0.356 mol * 6.022 x 10^23 atoms/mol
Therefore, the number of carbon atoms in the organic compound is approximately 2.144 x 10^23 atoms.