calculate the enegy needed to heat 500.g of ethanol from a temperature of -125.5 c to 78.5 c then boil it

first person with the correct equation and a good explanation of how to do this will get 50 fg

this should help you out: http://answers.yahoo.com/question/index?qid=20101008230658AA02eau

/e ofc use 78.5 instead of 78.3 in the link and also if you were given your own specific heat capacity/heat of vaporization, use those.

as for an explanation, the first equation (q=cmdT) is to find how much energy is needed to raise the temperature of ethanol from -125.5 to 78.5. the second equation is to determine how much energy is needed to vaporize (phase change) the amount of ethanol you have. lastly you just have to add both energies to get the total energy required

- also do note that in the heat of vaporization he used mass * heat of vaporization which is in units of kJ/mol <-- need to convert the g ethanol to mol for this part

This post was edited by cialda on Jun 9 2013 09:16pm