Question

If 95.6 mg of menthol burns completely in O₂ and gives 269 mg of CO₂ and 110 mg of H₂O, what is the number of moles of H that were present in this menthol sample?

A) 0.0061 moles
B) 0.0122 moles
C) 0.0754 moles
D) 0.121 moles
E) 0.242 moles

Answer 1

To find the number of moles of H in the menthol sample, we need to consider the balanced chemical equation for the combustion reaction and convert the mass of H2O produced into moles. The correct answer is A) 0.0061 moles.

Step-by-step explanation:

To find the number of moles of H in the menthol sample, we need to consider the balanced chemical equation for the combustion reaction. The balanced equation is:

C10H20O + 15O2 → 10CO2 + 10H2O

From the equation, we can see that for every mole of C10H20O combusted, 10 moles of H2O are produced. Since we know that 110 mg of H2O is produced, we can convert this mass into moles:

110 mg H2O * (1 g / 1000 mg) * (1 mol H2O / 18 g) = 0.0061 moles H2O

Since 10 moles of H2O are produced per mole of C10H20O, we can multiply the number of moles of H2O by the ratio:

0.0061 moles H2O * (1 mol C10H20O / 10 mol H2O) = 0.00061 moles H2O

Therefore, the number of moles of H that were present in the menthol sample is 0.00061 moles (or approximately 0.0061 moles). So the correct answer is A) 0.0061 moles.