ENTHALPY Flashcards
1
Q
definition of enthalpy change
A
heat energy change at constant pressure
kJmol-1
2
Q
definition of standard enthalpy change
A
enthalpy change measured under standard conditions
3
Q
enthalpy for exothermic reactions
A
deltah is negative
4
Q
enthalpy for endothermic reactions
A
deltah is positive
5
Q
how to measure enthalpy changes
A
need to know temp change and number of moles
thermometer
polystyrene cup
6
Q
sources of error when measuring enthalpy change
A
heat loss
incomplete reaction
7
Q
why are polystyrene cups used
A
good insulator
low specific heat capacity
8
Q
equation for heat loss/gain
A
q = mc delta T
m = mass in g
delta T = change in temperature
c = specific heat capacity of water (4.18)
9
Q
equation for delta T
A
delta T = -q/n
CONVERT Q TO KILAJOULES
