Chem Lab Experiment 8

Front 1

heat of combustion

Back 1

amount of heat energy released when a substance is completely burned

Front 2

General info about this lab?

Back 2

-determine how different chemical fuels produce heat energy (by finding the heat of combustion for a certain fuel)
-use calorimetry to measure the amount of heat produced when biodiesel is burned --> we will use the heat produced by burning the fuel to heat water (-qfuel=qwater)

Front 3

Water heat capacity, definition

Back 3

4.18 J/g*degreesC

4.18 J of energy is needed to raise the temp of 1 g of water by 1 degree C

Front 4

qwater =

Back 4

m(water)*Cp(water)*change in T of water

Front 5

Combustion procedure

Back 5

-set up calorimeter (ring stand, soda can filled w/ water, thermometer)
-make wick (soak wick in fuel, wrap in foil, place in scintillation vial)
-calibrate your calorimeter using 95% ethanol (can estimate calorimeter's heat capacity by solving q=mc*delta T
-repeat combustion procedure using each biodiesel sample and waste vegetable oil
-each time, record initial and final T, and initial and final mass of the whole thing
-let it burn until water's T rises about 10 degrees C, or until it burns out

Front 6

purpose of the ethanol experiment

Back 6

to give us a sense of how much heat the calorimeter will absorb from the burning flame --> use this data to calibrate our calorimetry experiment based on ethanol's heat of combustion

Front 7

the best way to determine the heat of combustion for a rxn..

Back 7

is to use a bomb calorimeter

Front 8

bomb calorimeter

Back 8

all of the heat from the combustion rxn is trapped inside a closed system
qcal=Ccal*detaT

Ccal=heat capacity of bomb calorimeter