Answer:
A) C₇H₆O₂
B) C₁₄H₁₂O₄
Explanation:
To determine the empirical and molecular formula of the compound, we need to follow a series of steps.
Step 1: Divide each percentage by the atomic mass of the element
C: 43.74/12.01 = 3.64
H: 3.14/1.01 = 3.11
O: 16.61/16.00 = 1.04
Step 2: Divide all the numbers by the smallest one, i.e. 1.04
C: 3.64/1.04 = 3.5
H: 3.11/1.04 = 3
O: 1.04/1.04 = 1
Step 3: Multiply all the numbers by 2, so that all of them are integers
C: 3.5 × 2 = 7
H: 3 × 2 = 6
O: 1 × 2 = 2
The empirical formula of the compound is C₇H₆O₂.
Step 4: Determine the molar mass of the empirical formula
M(C₇H₆O₂) = 7 × M(C) + 6 × M(H) + 2 × M(O)
M(C₇H₆O₂) = 7 × 12.01 g/mol + 6 × 1.01 g/mol + 2 × 16.00 g/mol = 122.13
Step 5: Calculate "n"
We will use the following expression
n = M(compound) / M(empirical formula)
n = (244.26 g/mol) / (122.13 g/mol) = 2
Step 6: Determine the molecular formula of the compound
We determine the molecular formula by multiplying the empirical formula by "n".
C₇H₆O₂ × 2 = C₁₄H₁₂O₄
