1. Heating curves and DH
temperature
added energy

2. Heating curves and DH
gas
liquid
temperature
solid
added energy

3. Heating curves and DH gas temperature liquid melting/ freezing pt
solid
added energy

4. Heating curves and DH boiling/ cond. pt gas temperature liquid
melting/
freezing pt
temperature
solid
added energy

5. Heating curves and DH boiling/ cond. pt gas temperature liquid
boiling/condensing
occurring here
melting/freezing
occurring here
boiling/
cond. pt
gas
liquid
melting/
freezing pt
temperature
solid
added energy

6. How is the total enthalpy change (DH) calculated
for a substance whose temperature change
includes a change in state?

7. temperature
Dt of solid
absorbing energy
added energy

8. temperature
DH = m x Csolid x Dt
added energy

9. as a solid melts becomes potential energy, so no Dt
the energy absorbed
as a solid melts becomes
potential energy,
so no Dt
temperature
DH = m x Csolid x Dt
added energy

10. DH = DHfus x # mols
temperature
DH = m x Csolid x Dt
added energy

11. Dt of liquid absorbing energy temperature DH = DHfus x # mols
DH = m x Csolid x Dt
added energy

12. DH = m x Cliquid x Dt temperature DH = DHfus x # mols
DH = m x Csolid x Dt
added energy

13. as a liquid boils becomes potential energy, so no Dt
the energy absorbed
as a liquid boils becomes
potential energy,
so no Dt
DH = DHfus x # mols
DH = m x Cliquid x Dt
temperature
DH = m x Csolid x Dt
added energy

14. DH = DHvap x # mols temperature DH = DHfus x # mols
DH = m x Cliquid x Dt
temperature
DH = m x Csolid x Dt
added energy

15. Dt of gas absorbing energy DH = DHvap x # mols temperature
DH = DHfus x # mols
DH = m x Cliquid x Dt
temperature
DH = m x Csolid x Dt
added energy

16. DH = m x Cgas x Dt DH = DHvap x # mols temperature DH = DHfus x # mols
DH = m x Cliquid x Dt
temperature
DH = m x Csolid x Dt
added energy

17. DH = m x Cgas x Dt
DH = DHvap x # mols
DH = DHfus x # mols
DH = m x Cliquid x Dt
temperature
DH = m x Csolid x Dt
added energy

18. being heated will be the sum of the DH of any Dt occurring plus
The DH of any substance
being heated will be the sum of the
DH of any Dt occurring plus
DH of any phase change occurring
DH = m x Cgas x Dt
DH = DHvap x # mols
DH = DHfus x # mols
DH = m x Cliquid x Dt
temperature
DH = m x Csolid x Dt
added energy

19. DH = m x Cgas x Dt DH = DHvap x # mols DH = DHfus x # mols
The DH of any substance
being heated will be the sum of the
DH of any Dt occurring plus
DH of any phase change occurring
DH = m x Cgas x Dt
DH = DHvap x # mols
DH = DHfus x # mols
DH = m x Cliquid x Dt
temperature
DH = m x Csolid x Dt
added energy

20. DH = m x Cgas x Dt DH = DHvap x # mols temperature DH = DHfus x # mols
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
DH = m x Cgas x Dt
DH = DHvap x # mols
DH = DHfus x # mols
DH = m x Cliquid x Dt
temperature
DH = m x Csolid x Dt
added energy

21. 50 oC temperature 0 oC -20 oC added energy
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
50 oC
temperature
0 oC
-20 oC
added energy

22. use the following values:
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
use the following values:
Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = J/goC
50 oC
temperature
0 oC
-20 oC
added energy

23. use the following values:
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
use the following values:
Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = J/goC
50 oC
DH3 = m x Cliquid x Dt
DH2 = DHfus x # mols
temperature
0 oC
DH1 = m x Csolid x Dt
-20 oC
added energy

24. DH1 = 10g x 2.1 J/goC x 20oC use the following values:
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
use the following values:
Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = J/goC
50 oC
DH3 = m x Cliquid x Dt
DH2 = DHfus x # mols
temperature
0 oC
DH1 = 10g x 2.1 J/goC x 20oC
-20 oC
added energy

25. use the following values:
DH2=10 g x 1mol/18g x 6.01kJ/mol
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
use the following values:
Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = J/goC
50 oC
DH2=10 g x 1mol/18g x 6.01 kJ/mol
DH3 = m x Cliquid x Dt
temperature
0 oC
DH1 = 10g x 2.1 J/goC x 20oC
-20 oC
added energy

26. DH3 = 10g x 4.186 J/goC x 50 oC use the following values:
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
use the following values:
Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = J/goC
DH3 = 10g x J/goC x 50 oC
50 oC
DH2=10 g x 1mol/18g x 6.01 kJ/mol
temperature
0 oC
DH1 = 10g x 2.1 J/goC x 20oC
-20 oC
added energy

27. total DH = DH1 + DH2 + DH3 use the following values:
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
use the following values:
Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = J/goC
total DH = DH1 + DH2 + DH3
DH3 = 10g x J/goC x 50 oC
50 oC
DH2=10 g x 1mol/18g x 6.01 kJ/mol
temperature
0 oC
DH1 = 10g x 2.1 J/goC x 20oC
-20 oC
added energy

28. total DH = DH1 + DH2 + DH3 = 420 J + 3340 J + 2093 J
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
use the following values:
Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = J/goC
total DH = DH1 + DH2 + DH3
= 420 J J J
DH3 = 10g x J/goC x 50 oC
50 oC
DH2=10 g x 1mol/18g x 6.01 kJ/mol
temperature
0 oC
DH1 = 10g x 2.1 J/goC x 20oC
-20 oC
added energy

29. total DH = DH1 + DH2 + DH3 5853 J = 420 J + 3340 J + 2093 J
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
use the following values:
Cice = 2.1 J/goc, DHfus H2O = 6.01 kJ/mol, CH2O liq = J/goC
total DH = DH1 + DH2 + DH3
5853 J = 420 J J J
DH3 = 10g x J/goC x 50 oC
50 oC
DH2=10 g x 1mol/18g x 6.01 kJ/mol
temperature
0 oC
DH1 = 10g x 2.1 J/goC x 20oC
-20 oC
added energy

30. It takes 5853 joules to heat up 10 grams
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
It takes 5853 joules to heat up 10 grams
of water from -20 oC to +50 oC.
DH3 = 10g x J/goC x 50 oC
50 oC
DH2=10 g x 1mol/18g x 6.01 kJ/mol
temperature
0 oC
DH1 = 10g x 2.1 J/goC x 20 oC
-20 oC
added energy

31. It takes 5853 joules to heat up 10 grams
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
It takes 5853 joules to heat up 10 grams
of water from -20 oC to +50 oC.
DH3 = 10g x J/goC x 50 oC
50 oC
DH2=10 g x 1mol/18g x 6.01 kJ/mol
temperature
0 oC
DH1 = 10g x 2.1 J/goC x 20 oC
-20 oC
added energy

32. 5853 J It takes 5853 joules to heat up 10 grams
EXAMPLE: What is DH for 10 g water with a total Dt from -20 oC to +50 oC?
It takes 5853 joules to heat up 10 grams
of water from -20 oC to +50 oC.
50 oC
temperature
0 oC
-20 oC
5853 J
added energy