Q.31E - Chemistry (OpenStax)

Question

Determine the empirical formula for the following compounds:

a) caffeine, C₆H₁₀N₄O₂ 

b) fructose, C₁₂H₂₂O₁₁

c) hydrogen peroxide, H₂O₂

d) glucose, C₆H₁₂O₆

e) ascorbic acid (vitamin C), C₆H₈O₆

Step-by-Step Solution

Answer

a) Empirical formula: C₄H₅N₂O

b) Empirical formula: C₁₂H₂₂O₁₁

c) Empirical formula: HO 

d) Empirical formula: CH₂O

e) Empirical formula: C₃H₄O₃

Step 1- Determine the definition of empirical formula

Empirical formula specifies the types of atoms present. It indicates the simplest whole-number ratio of the number of atoms (or ions) in the compound.  

Step 2- Take out the common factor to determine the empirical formula.

caffeine= 2 is the common factor, so the empirical formula will be C₄H₅N₂O

fructose= no common factor. so the empirical formula will be C₁₂H₂₂O₁₁

hydrogen peroxide = 2 is the common factor, so empirical formula will be HO

glucose= 6 is common factor, so empirical formula will be CH₂O

ascorbic acid= common factor is 2, so empirical formula will be C₃H₄O₃