http://ilab.psu.edu/models.html
Energetics 2A
5.2 Calculating Enthalpy Changes by Calorimetry
Reference: Higher Level Chemistry, p. 164 - 168
So how do you use ...
So how do you use ...
this
So how do you use ...
this
temperature
(ºC)
So how do you use ...
this
to find
temperature
(ºC)
So how do you use ...
this
to find
temperature
(ºC)
So how do you use ...
this
to find
temperature
(ºC)
energy (heat)
(1 Calorie = 4.18 kJ)
Basic Principles of Calorimetry
Calorimetry is ...
Basic Principles of Calorimetry
Calorimetry is ...
Basic Principles of Calorimetry
Calorimetry is ...
Basic Principles of Calorimetry
Calorimetry is ...
... an experimental measurement of the heat (enthalpy)
change of a reaction
Basic Principles of Calorimetry
Calorimetry is ...
... an experimental measurement of the heat (enthalpy)
change of a reaction
... an indirect measurement of the heat enthalpy change of
a reaction
Basic Principles of Calorimetry
Calorimetry is ...
... an experimental measurement of the heat (enthalpy)
change of a reaction
... an indirect measurement of the heat enthalpy change of
a reaction
... based on the principle of heat transfer
Basic Principles of Calorimetry
Calorimetry is ...
... an experimental measurement of the heat (enthalpy)
change of a reaction
... an indirect measurement of the heat enthalpy change of
a reaction
... based on the principle of heat transfer
∆heatsystem = -∆heatsurroundings
Basic Principles of Calorimetry
Calorimetry is ...
... an experimental measurement of the heat (enthalpy)
change of a reaction
... an indirect measurement of the heat enthalpy change of
a reaction
... based on the principle of heat transfer
∆heatsystem = -∆heatsurroundings
chemical reaction
Basic Principles of Calorimetry
Calorimetry is ...
... an experimental measurement of the heat (enthalpy)
change of a reaction
... an indirect measurement of the heat enthalpy change of
a reaction
... based on the principle of heat transfer
∆heatsystem = -∆heatsurroundings
chemical reaction
usually water
Basic Principles of Calorimetry
example:
heat of combustion of dehydrated, safflower oil
infused cuttings of Solanum tuberosum stems
direct measurement
indirect measurement
Basic Principles of Calorimetry
example:
heat of combustion of dehydrated, safflower oil
infused cuttings of Solanum tuberosum stems
direct measurement
burning potato chip
indirect measurement
Basic Principles of Calorimetry
example:
heat of combustion of dehydrated, safflower oil
infused cuttings of Solanum tuberosum stems
direct measurement
burning potato chip
indirect measurement
Basic Principles of Calorimetry
example:
heat of combustion of dehydrated, safflower oil
infused cuttings of Solanum tuberosum stems
direct measurement
✗
burning potato chip
indirect measurement
Basic Principles of Calorimetry
example:
heat of combustion of dehydrated, safflower oil
infused cuttings of Solanum tuberosum stems
direct measurement
✗
burning potato chip
indirect measurement
burning potato chip
Basic Principles of Calorimetry
example:
heat of combustion of dehydrated, safflower oil
infused cuttings of Solanum tuberosum stems
direct measurement
✗
burning potato chip
indirect measurement
burning potato chip
Basic Principles of Calorimetry
example:
heat of combustion of dehydrated, safflower oil
infused cuttings of Solanum tuberosum stems
direct measurement
✗
burning potato chip
indirect measurement
heat
burning potato chip
Basic Principles of Calorimetry
example:
heat of combustion of dehydrated, safflower oil
infused cuttings of Solanum tuberosum stems
direct measurement
✗
burning potato chip
indirect measurement
heat
burning potato chip
Basic Principles of Calorimetry
example:
heat of combustion of dehydrated, safflower oil
infused cuttings of Solanum tuberosum stems
direct measurement
✗
burning potato chip
indirect measurement
heat
burning potato chip
∆heatcombustion = -∆heatwater
Basic Principles of Calorimetry
combustion reactions (exothermic)
H2O
calorimeter
heat transferred
reaction
Basic Principles of Calorimetry
combustion reactions (exothermic)
H2O
calorimeter
heat transferred
reaction
Basic Principles of Calorimetry
combustion reactions (exothermic)
H2O
calorimeter
heat transferred
reaction
reaction releases heat
Basic Principles of Calorimetry
combustion reactions (exothermic)
H2O
calorimeter
heat transferred
reaction
reaction releases heat
water absorbs heat
Basic Principles of Calorimetry
combustion reactions (exothermic)
H2O
calorimeter
heat transferred
reaction
reaction releases heat
water absorbs heat
temperature of water increases
Basic Principles of Calorimetry
reactions in aqueous solution
exothermic reactions
H2O
endothermic reactions
calorimeter
heat transferred
reaction
Basic Principles of Calorimetry
reactions in aqueous solution
exothermic reactions
H2O
endothermic reactions
calorimeter
heat transferred
reaction
Basic Principles of Calorimetry
reactions in aqueous solution
exothermic reactions
endothermic reactions
calorimeter
H2O
heat transferred
reaction
reaction releases heat
Basic Principles of Calorimetry
reactions in aqueous solution
exothermic reactions
endothermic reactions
calorimeter
H2O
heat transferred
reaction
reaction releases heat
water absorbs heat
Basic Principles of Calorimetry
reactions in aqueous solution
exothermic reactions
endothermic reactions
calorimeter
H2O
heat transferred
reaction
reaction releases heat
water absorbs heat
temperature of solution
increases
Basic Principles of Calorimetry
reactions in aqueous solution
exothermic reactions
endothermic reactions
calorimeter
H2O
H2O
heat transferred
reaction
reaction releases heat
water absorbs heat
temperature of solution
increases
reaction
Basic Principles of Calorimetry
reactions in aqueous solution
exothermic reactions
endothermic reactions
calorimeter
H2O
H2O
heat transferred
reaction
reaction releases heat
water absorbs heat
temperature of solution
increases
reaction
Basic Principles of Calorimetry
reactions in aqueous solution
exothermic reactions
endothermic reactions
calorimeter
H2O
H2O
heat transferred
reaction
reaction
reaction releases heat
reaction absorbs heat
water absorbs heat
temperature of solution
increases
Basic Principles of Calorimetry
reactions in aqueous solution
exothermic reactions
endothermic reactions
calorimeter
H2O
H2O
heat transferred
reaction
reaction
reaction releases heat
reaction absorbs heat
water absorbs heat
water loses heat
temperature of solution
increases
Basic Principles of Calorimetry
reactions in aqueous solution
exothermic reactions
endothermic reactions
calorimeter
H2O
H2O
heat transferred
reaction
reaction
reaction releases heat
reaction absorbs heat
water absorbs heat
water loses heat
temperature of solution
increases
temperature of solution
decreases
Basic Principles of Calorimetry
Assumptions made:
Basic Principles of Calorimetry
Assumptions made:
1. complete transfer of heat energy between the water
and the reaction
Basic Principles of Calorimetry
Assumptions made:
1. complete transfer of heat energy between the water
and the reaction
... aka ... no heat transfer from the reaction to the
reaction vessel or thermometer or surrounding air
Basic Principles of Calorimetry
Assumptions made:
1. complete transfer of heat energy between the water
and the reaction
... aka ... no heat transfer from the reaction to the
reaction vessel or thermometer or surrounding air
2. specific heat capacity and density of a dilute solution is
the same as water (more info on this in the next episode)
Basic Principles of Calorimetry
Assumptions made:
1. complete transfer of heat energy between the water
and the reaction
... aka ... no heat transfer from the reaction to the
reaction vessel or thermometer or surrounding air
2. specific heat capacity and density of a dilute solution is
the same as water (more info on this in the next episode)
dilute solution ≤ 1 mol dm-3
Basic Principles of Calorimetry
Assumptions made:
1. complete transfer of heat energy between the water
and the reaction
... aka ... no heat transfer from the reaction to the
reaction vessel or thermometer or surrounding air
2. specific heat capacity and density of a dilute solution is
the same as water (more info on this in the next episode)
dilute solution ≤ 1 mol dm-3
D = 1.00 g cm-3
Basic Principles of Calorimetry
Assumptions made:
1. complete transfer of heat energy between the water
and the reaction
... aka ... no heat transfer from the reaction to the
reaction vessel or thermometer or surrounding air
2. specific heat capacity and density of a dilute solution is
the same as water (more info on this in the next episode)
dilute solution ≤ 1 mol dm-3
D = 1.00 g cm-3
cH2O = 4.18 J g-1 ºC-1