HW Problem 8.37 Need Help

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HW Problem 8.37 Need Help

Postby 104781135 » Sat Jan 28, 2017 9:38 pm

Hello everyone, could someone please help me with problem 8.37? I'm not sure what step to take first.

a) At its boiling point, the vaporization of 0.597 mol CH4(l) requires 4.76kJ of heat. What is the enthalpy of vaporization of methane? b) An electric heater was immersed in a flask of boiling ethanol, C2H5OH and 22.45g of ethanol was vaporized when 21.2kJ of energy was supplied. What is the enthalpy of vaporization of ethanol?

Thank you.

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Joined: Fri Jul 15, 2016 3:00 am

Re: HW Problem 8.37 Need Help

Postby Terry1A » Sat Jan 28, 2017 10:13 pm

At standard temperature and constant pressure, the enthalpy of vaporization is the value needed to vaporize 1 mol of a given molecule. For 8.37 a) you can create a proportion in order to solve for the enthalpy of vaporization: 0.579 mol CH4 / 4.76 kJ = 1 mol CH4 / X, and then solve for X. You also do the same for b) except you first convert g to moles.

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