Cliffs AP Chemistry, 3rd Edition

∆E= ∆H– RT∆n= ∆H– P∆V= q + w

∆H= ∆E + ∆(PV) = q – w + P∆V

w= −P∆V= −nRTlnV

V

i

f

Done on a system Done by a system

Work, w +w −w

Heat, q +q(endothermic) −q(exothermic)

• “bomb” calorimeter
  ∆E= qv(valid with constant volume: “bomb” calorimeter)
  qreaction= −(qwater+ qbomb)

qbomb = C ⋅∆t

where C= calorimeter constant (heat capacity) in J/°C.

• “coffee cup” calorimeter
  ∆H= qp(valid with constant pressure: “coffee cup” calorimeter)

q = m⋅c ⋅∆t

t

Cp H

∆

=∆

H H

products

reactants

reaction path

Exothermic

(heat released)

H H −

products

reactants

reaction path

Endothermic

(heat absorbed)

+

Part II: Specific Topics