5.
1 Introduction to Thermodynamics
pp.278-290
Thermochemistry is the study of the _________ changes involved in chemical and
physical processes. energy
A sample under observation is referred to as a system
_________and everything not in the
system (____________________) is in the universe
surroundings
universe = system + surroundings
Types of Systems:
C
1. Open System: can exchange both ________ andmatter
_____ with its surroundings.
E
2. Closed System: can exchange _______, but notmatter
_____, with its surroundings.
3. Isolated System: cannot exchange energy or matter with its surroundings.
Teenydifficult
to achieve
instapot
pressure cooker
potonstove pot on the
withnolid stovew alid
Thermal energy is the sum of the kinetic
________ energy of each particle of a system.
− cannot
_________ be measured
Temperature is the __________ kinetic energy of all the particles of a system.
− can average
_______ be measured
First Law of Thermodynamics
Energy can be converted
____________ from one form to another BUT cannot be
created
_______________ or _______________.
destroyed
Euniverse is CONSTANT!
E cannot be
Euniverse = 0 created or destroyed!
Only transformed.
a
d change in
Euniverse Esystem Esurroundings
Esystem Esurroundings
a
Esystem =0- Esurroundings
e
Second Law of Thermodynamics
1. When two objects are in thermal contact, heat is always transferred from the
until the two objects are at the _________
lower
object at a __________ temperature to the object at a _________ temperature
higher temperature.
same
disorderedwith time (aka ________).
2. Every isolated system becomes more _____________
entropy
a
degree of disorder
disorder
degreeof
Third Law of Thermodynamics
Entrop reaches a constant alue doesn t change) as it approaches -273.15°C,
absolute zero
which is called _______________________
ftp.intatwhich
particlestheoretically Kelvin
a stop allmotion
Ek 0
O
Calculating the Change in Energy
The amount of heat entering/leaving a system can be calculated:
0
Q = m · c · ΔT
where heat measuredinJoules
Q = ______________ J
m = mass
______________
Cg
c = ___________________________
specificheatcapicity
ΔT = __________________________ Jtg
change intempfocorok
Specific Heat Capacity (c) is the amount of energy needed to increase the
temperature of ______ of a substance by _____
1g 10410k
Substance Specific Heat Capacity Substance Specific Heat Capacity Substance Specific Heat Capacity
(J/g·°C) (J/g·°C) (J/g·°C)
Elements Compounds Mixtures
Aluminum 0.897 Ammonia 4.70 Air 1.01
(liquid)
Carbon 0.709 Ammonia 2.06 Concrete 0.88
(graphite) (gas)
Copper 0.385 Ethanol 2.44 Glass 0.84
Gold 0.129 Water (solid) 2.00 Granite 0.79
FT
Hydrogen 14.304 Water 4.19 Wood 1.26
(gas) (liquid)
Iron 0.449 Water (gas) 2.02
t ta
Example: When 600g of water in an electric kettle is heated from 20°C to 85°C to
make a cup of tea, how much heat flows into the water?
Q
Q me At
m 600g
Q 2600 to19
c 4.19 GSI
Dt 85 20 Q 163410J
65 C 2 102 KJ
Q 2 1058
IKI 1000J
HW: p.281 #1-10, p.291 #2,5,6,7 c values are on
f p 743 or p 280
answers
on
P765
answers on P 767
