A 0.5438 g sample of a compound contains only C H and O was burned completely in oxygen.the products were 1.0390 g CO2 and 0.6369g H2O. Determine the empirical formula of thr compound
C6H1803
what is the difference between atomic mass and molecular mass? Isn't the atomic mass and molecular mass of carbon 12?
To determine the empirical formula of the compound, we need to find the ratio of elements present in the compound.
1. Start by finding the number of moles of carbon dioxide (CO2) produced.
- The molar mass of carbon dioxide (CO2) is 44.01 g/mol.
- Divide the mass of CO2 (1.0390 g) by its molar mass (44.01 g/mol) to get the number of moles of CO2.
Moles of CO2 = mass of CO2 / molar mass of CO2
= 1.0390 g / 44.01 g/mol
2. Find the number of moles of water (H2O) produced.
- The molar mass of water (H2O) is 18.02 g/mol.
- Divide the mass of H2O (0.6369 g) by its molar mass (18.02 g/mol) to get the number of moles of H2O.
Moles of H2O = mass of H2O / molar mass of H2O
= 0.6369 g / 18.02 g/mol
3. Determine the moles of carbon, hydrogen, and oxygen present in the compound.
- From the balanced chemical equation for the combustion, we know that 1 mole of CO2 contains 1 mole of carbon (C) and 2 moles of oxygen (O). Therefore, the number of moles of carbon (C) in the compound is equal to the moles of CO2.
- Similarly, from the balanced chemical equation, we know that 1 mole of H2O contains 2 moles of hydrogen (H) and 1 mole of oxygen (O). Therefore, the number of moles of hydrogen (H) in the compound is equal to twice the moles of H2O.
- The number of moles of oxygen (O) in the compound can be calculated by subtracting the moles of carbon and hydrogen from the total moles of oxygen in the CO2 and H2O.
Moles of C = Moles of CO2
Moles of H = 2 * Moles of H2O
Moles of O = (Moles of CO2 * 2) + Moles of H2O
4. Simplify the ratio of moles by dividing each by the smallest number of moles obtained in step 3.
- This will give you the simplest whole number ratio of moles.
5. Finally, write the empirical formula using the whole numbers obtained in step 4.
- The subscripts of the elements in the empirical formula represent the ratio between the number of atoms in the compound.
For example, if the ratio of moles of C : H : O is 2 : 4 : 1, then the empirical formula would be C2H4O.
Repeat the above steps to calculate the empirical formula of the compound using the given mass data.
g C = 1.0390g CO2 x (atomic mass C/molar mass CO2) = ?
g H = 0.669 g H2O x (2*atomic mass H/molar mass H2O) = ?
g O = 0.5438-gC-gH = ?
Then mols C = grams C/atomic mass C = ?
mols H = grams H/atomic mass H = ?
mols O = grams O/atomic mass O = ?
Now find the whole number ratio of C:H:O
Post your work if you get stuck.