Determine the enthalpy of vaporization, in [tex]$kJ / mol$[/tex], of [tex]$CH_3OH$[/tex] if 14.5 kJ of heat is needed to vaporize 0.500 moles of [tex][tex]$CH_3OH$[/tex][/tex].



Answer :

To determine the enthalpy of vaporization of [tex]\( \text{CH}_3\text{OH} \)[/tex] (methanol), follow these steps:

1. Identify and list the given data:
- The amount of heat needed to vaporize methanol, [tex]\( Q \)[/tex], is 14.5 kJ.
- The number of moles of methanol, [tex]\( n \)[/tex], is 0.500 moles.

2. Recall the formula for the enthalpy of vaporization ([tex]\( \Delta H_{\text{vap}} \)[/tex]):
[tex]\[ \Delta H_{\text{vap}} = \frac{Q}{n} \][/tex]
where:
- [tex]\( \Delta H_{\text{vap}} \)[/tex] is the enthalpy of vaporization in kJ/mol.
- [tex]\( Q \)[/tex] is the heat required in kJ.
- [tex]\( n \)[/tex] is the number of moles of the substance.

3. Substitute the given values into the formula:
[tex]\[ \Delta H_{\text{vap}} = \frac{14.5 \text{ kJ}}{0.500 \text{ moles}} \][/tex]

4. Perform the division to find the enthalpy of vaporization:
[tex]\[ \Delta H_{\text{vap}} = \frac{14.5}{0.500} = 29.0 \text{ kJ/mol} \][/tex]

Therefore, the enthalpy of vaporization of [tex]\( \text{CH}_3\text{OH} \)[/tex] is [tex]\( 29.0 \text{ kJ/mol} \)[/tex].