a compound has an empirical formula CH20 and molecular mass of 90 determine it's molecular formula(H=11; C=12; 0=16)
empirical mass CH2O is 12 + 2 + 16 = 30
The molar mass is 90.
empirical mass x #units = molar mass
30*units = 90
so you must have (CH2O)3 or
C3H6O3. Check it.
3*12 = 36
6*1 = 6
3*16 = 48
48 + 6 + 36 = 90
To determine the molecular formula of a compound, we need to know the empirical formula and the molecular mass. The empirical formula represents the simplest, most reduced ratio of the atoms in a compound, while the molecular formula specifies the actual number of atoms of each element in a molecule.
Let's start by calculating the empirical formula mass of the compound, which is the sum of the atomic masses of all the elements in the empirical formula. We are given the following atomic masses: H = 1, C = 12, O = 16.
Empirical formula mass = (number of carbon atoms × atomic mass of carbon) + (number of hydrogen atoms × atomic mass of hydrogen) + (number of oxygen atoms × atomic mass of oxygen)
Empirical formula mass = (1 × 12) + (2 × 1) + (1 × 16) = 12 + 2 + 16 = 30
Next, we calculate the ratio between the molecular mass and the empirical formula mass:
Ratio = Molecular mass / Empirical formula mass
Ratio = 90 / 30 = 3
This means that the molecular formula contains three times the number of atoms as the empirical formula.
Now let's determine the molecular formula:
Molecular formula = (empirical formula) × Ratio
Molecular formula = (CH2O) × 3 = C3H6O3
Therefore, the molecular formula of the compound is C3H6O3.
To determine the molecular formula of a compound, you need to know the empirical formula and the molar mass of the compound.
The empirical formula of the compound is CH₂O. This means that for every 1 carbon (C) atom, there are 2 hydrogen (H) atoms, and 1 oxygen (O) atom.
Next, calculate the molar mass of the empirical formula.
Molar mass of C = 12 g/mol
Molar mass of H = 1 g/mol
Molar mass of O = 16 g/mol
Molar mass of CH₂O:
(12 g/mol x 1) + (1 g/mol x 2) + (16 g/mol x 1) = 12 g/mol + 2 g/mol + 16 g/mol = 30 g/mol
Now you have the molar mass of the empirical formula, which is 30 g/mol.
Given that the molecular mass of the compound is 90 g, divide the molecular mass by the molar mass of the empirical formula to find the ratio:
90 g/mol / 30 g/mol = 3
This means that the molecular formula of the compound is three times the empirical formula: (CH₂O)₃.
Therefore, the molecular formula of the compound is C₃H₆O₃.