MEASURING ENERGY CHANGES
Calorimeter—a device used to measure energy given off or absorbed during chemical changes.

Reinforce the LAW OF CONSERVATION OF ENERGY

EXAMPLE AND DRAWING OF AN EXO REACTION
Will temperature of the water go up or down?

EXAMPLE AND DRAWING OF AN ENDO REACTION
Will temperature of the water go up or down?

SPECIFIC HEAT
SPECIFIC HEAT (Cp)—the heat required to raise the temperature of one gram of substance by one Celcius degree.   Every substance has its own specific heat. (specific value)

1 g Water  = 4.148 J/gCº
1 g Al = .902 J/gCº

A-3 A-5 HAVE ALL THE SPECIFIC HEATS
Heat required to raise the temp. of one gram of water, one Celcius degree is 4.184 Joules.  The specific heat of water is 4.148 J/gCº

HOW CAN ONE MEASURE HEAT LOST OR HEAT GAINED

q = (m) * (?T) * (Cp)

 SYMBOL DESCRIPTION UNIT Q heat gained or lost by the water (J) M mass in grams (g ) DT change in temperature (Ti– Tf) Ti = temperature initial Tf = temperature final (ºC) Cp specific heat (J / g * Cº)

How much heat is lost when a solid aluminum ingot with a mass of 4000 g cools from 500ºC to 100ºC?
CAl = .903 J / g * Cº

q = (4000 g) * (500-100ºC) *  (.903 J / g * Cº)

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