Answer:
The molecular formula of this compound is C4H4N2O2
Explanation:
Step 1: Data given
Mass of the compound = 84 mg
The compound contains:
36 mg of Carbon
3 mg of hydrogen
21 mg of nitrogen
24 mg of oxygen
Molar mass of carbon = 12.01 g/mol
Molar mass of hydrogen = 1.01 g/mol
Molar mass of nitrogen = 14 g/mol
Molar mass of oxygen = 16 g/mol
Step 2: Calculate number of moles
Moles = mass / molar mass
Moles of carbon = 0.036 g/ 12.01 g/mol = 0.003 moles
Moles of hydrogen = 0.003 g/ 1.01 g/mol = 0.003 moles
Moles of nitrogen = 0.021 g/ 14 g/mol = 0.0015 moles
Moles of oxygen = 0.024 g/ 16 g/mol = 0.0015 moles
Step 3: Calculate mol ratio
We divide by the smallest amount of moles
C: 0.003 / 0.0015 = 2
H: 0.003 / 0.0015 = 2
N = 0.0015/0.0015 = 1
O = 0.0015/0.0015 = 1
The empirical formula is C2H2NO
The molecular mass of this empirical formula is 56 g/mol
Step 4: Calculate the molecular formula
We have to multiply the empirical formula by n
n = 112 g/mol / 56g/mol = 2
We have to multiply the empirical formula by 2
Molecular formula = 2*(C2H2NO) = C4H4N2O2
The molecular formula of this compound is C4H4N2O2
