Question

calculate the amount of heat needed to boil 15.5 g of methanol (ch₃oh). the molar heat of vaporization for methanol is 35.21 kj/mol. the molar mass of methanol is 32.04 g/mol.
○ 72.78 kj
○ 17.03 kj
○ 35.21 kj
○ 545.8 kj

Explanation:

Step1: Calculate moles of methanol

Moles = $\frac{\text{mass}}{\text{molar mass}}$, mass = 15.5 g, molar mass = 32.04 g/mol.
Moles = $\frac{15.5}{32.04} \approx 0.4837$ mol.

Step2: Calculate heat required

Heat ($q$) = moles × molar heat of vaporization.
Molar heat of vaporization = 35.21 kJ/mol.
$q = 0.4837 \times 35.21 \approx 17.03$ kJ.

Answer:

17.03 kJ (Option: 17.03 kJ)