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Benzoic acid contains 68.8% carbon, 4.95% hydrogen, and 26.25% oxygen. Find the empirical formula of benzoic acid.

User Timothy
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1 Answer

4 votes

Answer:

C7H6O2

Step-by-step explanation:

Let;

68.8% of Carbon represents 68.8g

4.95% of Hydrogen represents 4.95g

26.25% of Oxygen represent 26.25g

Next, we convert each gram value to mole value by dividing by their respective molar mass {C = 12, H = 1, O = 16}

C = 68.8/12 = 5.73 mol

H = 4.95/1 = 4.95 mol

O = 26.25/16 = 1.64 mol

Next, we divide each mole value by the smallest (1.64mol)

C = 5.73 ÷ 1.64 = 3.49

H = 4.95 ÷ 1.64 = 3.02

O = 1.64 ÷ 1.64 = 1

Next, we multiply each ratio by 2 to obtain our simplest whole number ratio (empirical formula)

C = 3.5 × 2 = 7

H = 3.02 × 2 = 6

O = 1 × 2 = 2

Hence, the ratio of C, H and O is 7:6:2 and the empirical formula of benzoic acid is C7H6O2

User Tabitha
by
8.1k points
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