# If/ ~he'iOre = o~ sys

## Transcription

If/ ~he'iOre = o~ sys
```• H
1S a
rm
energy
II
system + surroundings = universe
• state functions depend only on the s
e of a
stem, n
upon
e way it reached th
st
Example: the di tance to my house from school, as
the crow flies is the same. I m
many
di
rent rou
home and
e
di stance
traveled may be vastly different but the straight
line dis
ce from the school 1S the same (a s
fun
on),
• heat flows from a sample
a higher temperature
1n
one
a lower tem r urea q = h
q = +
when heat flows into the sys
from the
surroundings ( q !tlna1
.
- q 1n,.l:u,1
.. = +)
and q = -' • when
he
owsout OT the system to the surround1ngs.
where m == mass" c == spe
c h
(an
intensive property), and t == temperature in
sius.
II
1 cal= 4.18 joules
specific heat of water - 4.18 jig
or 1
IgOc
II
ex hermic = he
flows out of the system,
endothermic - heat flows into the sys
II
c orlm ry - a method of making thermochemical
measurernen
this means the heat flow for
~he'iOre = o~ sys
will be equal in magnitude but
th
r the
orlm er and
opposi
in si gn
its contents.
constant pressure - ~J{=
nce most re
ons
ke place 1n open
atmospheric pressure we have a spe
this heat at constant pressure. We
II
If/ II
ons
- and
for
hermic r
+
ons
rst Law of
the
II
Law of conserv
on of Energy
Thermodyamics.
II In
any process,
e total change 1n energy of the system, ~E = q + w .
you do work on the sys w > 0, and the energy of the system goes up.
(E is call
e intern
energy). Energy (in rn
energy) is a state function. In
thermodynamics we don't worry about absolute
ene ies ( way too complic ed m be impossible to
II Norne ----------------­
READING THERMOMETERS
What temperature is indicated on each of the thermometers below?
60
2.0
10
5
o
70
----m-- 10
-~--5
--...._--10
- - m - - 60
a)
b)
--_w_-
c)
10
30
--m--25
-10
g)
Chemistry IF8766
2.0
27
-0
-_D_-
10
26
o
25
- 10
f)
e)
d)
0
20
5
100
10
0
aq
0
-5
%
-10
-/0
q7
-20
-15
q6
h)
i)
5
©Instructional Fair, Inc.
HEAT
DEF INIliON
UNITS
MERSURING
DEUICE
TEMP.
t
•
emp ratul-e OOOe
OOoe
'-­
BOILING WATER
\'71Ii4~11
C"olltailler of
Explaill \\711)7",
LING
"7at{~r
t-ontains UIOI"e )Ieat?
Name _________
TEMPERATURE AND ITS MEASUREMENT Temperature (which measures average kinetic
of
molecules) can be
measured using three common scales: Celsius, Kelvin and Fahrenheit. We use the . .
following formulas to convert from one scale to another. Celsius is the
most
Fahrenheit is the old
desirable for laboratory work. Kelvin represents the absolute
English scale which Is never used in lab.
Complete
following chart. All measurements are good to 1°
or better.
450 K
98.6 0 F
c
294 K
K
,
.....
Name
~-------------------M. Rudder
Block------'---­
PROBLEMS - Quiz
SHOW ALL WORK AL''» USE UNITS
LHow
2. How
IS
LIJ;OvU';;;'U
must
to change
of ice at _5° C to water at 50
to change 100 g ofwater at 100
to steam at 220°C?
tenmerature graphs showing the changes that occur
two
HEAT PROBLEMS - PRACTICE TRIADS 1.
much heat is needed to "'.........F,'" 10 g of ice at
2. How
heat must
Sketch a
vs.•
previous problems.
'-"UJLjJ .....
C to water at
°c? removed to change 100 g of steam at llO °C to water ar 20°C?
~
graph sho"wing
changes that occur for
ofthe two
F~E
Nome
NG AND BOILING POINT GRAPH
----------------­
25
~ 15
d
b
Energy - - f j I >
Answer
following
1, What is
using
point of the substa What is the boiling point of
substance? _ _ __ 3. What is the melting point of
4. What
substance? _ _ __
is being warmed? _ _ __
represents the range where
What letter
where the liquid is being warmed? _ _ __
6.
What letter represents the range
7,
What
8, . What the vapor is being warmed? _ _..__
melting of the solid? _ _ __ vaporization
the liquid?
9. What letter(s) shows a change in potentia! energy? _ _ __
10. What letter(s) shows a
in kinetic
11, What letter
condensation? 1
crystallization? _ _ __
What 13 ©:nstructionai Fair, Inc.
Name _________
IEAT AND ITS MEASUREMENT
"or energy) can be measured in units of calories or joules. \Nhen there is a
mperature change (~n, heat (Q) con be calculated using this formula:
3\...
Q = mass x ~ T x specific heat capacity
(~T
= Final Temp - Initiol Temp)
Jring a phose change, we use this formula:
II Q = mass x heat of fusion (or heat of vaporization) I
)Ive the following problems.
1.
How many joules of heat are given off when 5.0 g of water cool from 75° C
to 25° C? (Specific heat of water = 4.18 j/gO C)
/
How many calories are given off by the water :n Problem 1?
(Specific heat of water = 1.0 col/gO C)
3.
How many joules does it take to melt 35 g
4.
How many calories are given off when 85 g of
(heat of vaporization = 539.4 col/g)
5.
How many joules of heat are necessary to rc :se the temperature of 25 g of water
from 10 C to 60° C?
Of
ice at 0° C? (heat of fusion
s~eam
= 333 jig)
condense to liquid water?
0
How many calories are given off when 50 g
(heat of fusion = 79.72 col/g)
helT'~-;Y
IF8766
~5
o~
water at 0° freezes?
©lnstructionoJ Fair, Inc.
Date
Name
CHAPTER 5 REVI
Class
ACTIVITY
Text Reference: Section 5-5
Temperature
Answer the following questions.
1. a. How many Fahrenheit
of water?
h. What are these two
2. a. How many Celsius
of water?
the
f1&:>dr<>&:>"
1"1'<',<>'71ro<1
and boil-
l.a.
t"<>Ynn,<>r~ln h.
the
f1&:>dr<'<'"
and
2.a.
uvuU'F.
h.
h. What are these two temperatures? c. How does the size of a Celsius
Fahrenheit "",ocr",,,,
d. What is the lowest
compare V\rith that of a
d.
in "C?
IJV,;,,,.,vn,,
3. a. How many kelvins
water?
c.
and
of
3.a.
h.
h. What are these two c. How does the size of a kelvin compare with that of a
VC:J''''H.L;)
c.
d. What is the lowest possible temperature in kelvins?
d.
e. \\That is this lowest
e.
lJv;",nlu""
4. Convert Celsius
values in the temperature called?
and kelvins as necessary to find the
below. Use the fonnulas
K
°C + 273
cC = K 273
"
(a)
+ - - - - - BOO(
-_--oj_r<
== 383 K
C(
==
323
O(
loce
4.a.
K ----j-
h.
K----+
c.
==
K
d.
-1O o e ==
K
e.
°C
=:
243 K
l
COPYRIGHT by Prentice Hall. Inc.
Reproduction of this master is restricted to duplication for classroom use only,
f.
CHEMISTRY: The Study of Matter
5-7
D
Name
ass
5 REVIEW ACTIVITY
Text Reference: Section 5-6
Calorimetry
Answer
following questions.
1. a. The non-SI unit in which the
of heat energy has com­
manly been
is called the _ __
h. The SI-derived unit that is now the
ing this quantity is called the _ __
unit for e:x.1Jress­
2. a. The
of heat energy
to raise the
of a unit mass of a substance
1DC is called the _-'-_ of the
substance.
b. The value of this
for water, in SI-derived units, is
1. a.
h.
2.a.
h.
thermometer
material
water -I-+-­
Calorimeter
3.
ll.
8A x
or
reaction chamber
In the
shown in the
a reaction that releases
J of heat energy
Is this
endothennic
b.
that the calorimeter contains 5.00 x 10 2 g of water
and
is
what vvill the final tem­
perature be? Choose your answer from among the
and
write the letter of the correct answer in the blank.
1. 4.0DC
4.
2.
5. 40,QOC
3. 2B.O°C
5-8
CHEMISTRY' Th" <;t"r1V nf MattE'r
COPYRIGHT by Prentice Hall, Inc.
3. a.
b.
```

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