Chap 6 Chem 1110

Adiabatic Wall

perfect insulator

Diabetic Wall

perfect conductor of heat

Open system

mass transfer between systems and surroundings

closed system

system at constant mass

process

change in internal energy due to change in heat and/or work between system and surroundings

ΔE<0

energy is released to surroundings, q is released to surroundings, w is done BY the system

ΔE>0

energy absorbed from surroundings, q absorbed from surroundings, work done by system

+q

sys gains heat

-q

sys released heat

+w

work done ON the system

-w

work done BY system

1 J

1 kg m^2/s^2

1 cal

4.184 J

1000 cal

1 kcal (1 Cal)

w =

(-P)(ΔV)

ΔE =

q + w

ΔH = ΔE

- reactions that do not involve gases
-reactions in which the total amount of mol of gas does not change
-reactions in which q sub p is much larger than PΔV, even if the total mol of gas does change

ΔH<0

heat out

ΔH>0

Heat in

exothermic

Releases heat

Endothermic

Absorbs heat

q

heat lost or gained

c specific heat capacity (J/g K)

quantity of heat required to change the temperature of 1 g of substance by 1 k

C heat capacity (cm)

quantity of heat required to change a substance's temperature by 1 K

m

mass in g

molar heat capacity

q/(amount in mol)(ΔT)