4/29/2013 and 4/30/2013 Standards: 7 (Chemical Thermodynamics)
Objectives:
● Students will be able to calculate 2 problem types:
a. specific heat problems
b. heats of vaporization or fusion
DO NOW:
1. Given: 3.70 J and ΔT -21 ---> -41 Find: mass of water
2. Given: 2.25 mol methanol
Find: kJ required to vaporize if at
-33.3 °C
(bp of methanol)
HOMEWORK:
1. None
===========================================================
BASKET: ● Journal 4/26 (What you learned, or relearned about (for heat of vaporizaiton)
specific heat calcs and heats of vaporization and fusion)
===========================================================
Please check to see if you accidently
put a "W" eraser in your backpack.
Who goes with What?
Specific Heat J/g°C
Heat of fusion
kJ/mol
Heat of Vap kJ/mol
slopes
Given
Find
Given
°C
Find
flat lands
g °C
J
flat lands
kJ
mol
mol
J
4.18
Find
kJ
g
J
Given
g
°C
kJ
6.02
mol
flat lands
slopes
kJ
mol
Make up problems for all 3 boxes above and work out in the box provided above.
40.6 kJ
mol
Name:_______________ Date:_______ Period:__
Direct
ions:
Pract. Probs. Ch 16.3 - Thermochem. Eqns.
Show
Specific heat - practice problems
ΔT
Q#
J
mass
1
find
2.5 kg
0°C ---> 32°C
2
39.5 J
find
100°C ---> 145°C
3
148 J
725 g
find
4
2.05 J
find
-82°C ---> -5°C
5
find
82 g
74°C ---> 30°C
Heat of Vaporization/Fusion - practice problems
Q#
6
7
8
9
10
mol
substance
kJ
5.5
find
water
find
22.5
ammonia (NH3)
find
83.1
methanol
1.7
find
ethanol
find
2.6
NH3
This page was use to make:
http://mrwiggersci.com/chem/homework/Ch-16-3-PPs-sp-ht-vap-fusion.htm
calcs!
Answer
questio
ns next
to each
line, or
number
1-10 on
back
and
show
calcs
there
with
note on
front to
look at
the
back.
1. Given: 3.70 J and ΔT -21 ---> -41 deg C
Find: mass of water
2.0
J
sp ht H2O solid
g °C
0.0925 g
H2O
2. Given: 2.25 mol methanol
Find: kJ required to vaporize if at
-33.3
°C (bp of methanol)
Specific Heat & Heats of Fusion & Vap
«grade»
Grade:
«subject»
Subject:
«date»
Date:
1
For specific heat problems, if you are given mass and J
(joules), what will the find be?
A
ΔT
B
mol
C
J
D
g
For specific heat problems, if you are given mass and ΔT,
what will the find be?
2
A
ΔT
B
J
C
g
D
mol
For Specific Heat problems, if you are asked to find ΔT what
information must you be given to be able to solve the
problem? (there may be more than one correct answer,
choose all that apply, or none)
3
A
J
B
ΔT
C
g
D
mol
E
all of these are needed
F
none of these are needed
4
For heat of vaporization problems, if you are given grams of He,
what will you need to do to solve the problem?
A
use specific heat and solve for kJ
B
change grams to moles and use heat of fusion to solve the
problem
C
change grams to moles and use heat of vaporization to solve the
problem
D
you cannot solve this problem
5/1/2013 Standards: 7 (Chemical Thermodynamics)
Objectives:
● Students will be able to calculate 2 problem types:
a. specific heat problems
b. heats of vaporization or fusion
DO NOW:
1. Classwork working problems from SmartBoard
HOMEWORK:
1. Ch 16.2 p. 498 #12 & 13; Ch 16.3 p. 504 20, 21, 22 (5 pts) Std 7
(students will grade each others homework tomorrow)
===========================================================
● Journal 4/30 (What you learned, or relearned about
calcs and heats of vaporization and fusion)
specific
10
mi
n
make trying a
habit
marriage
must be
Wife blows
forever
up at
sex
husband
coming home
after work
TRY
Choose wisely!
Always look for what you did wrong first,
be the leader!
hap
py
wife
hap
py
life
/
Who goes with What?
Specific Heat J/g°C
Heat of fusion
kJ/mol
flat lands
Given
Find
Given
slopes
°C
J
Find
mol
mol
kJ
Heat of Vap kJ/mol
flat lands
Given
Find
kJ
g
J
40.6
g
°C
kJ
mol
flat lands
slopes
kJ
mol
4.18 J
g °C
6.02
kJ
mol
Make up problems for all 3 boxes above and work out in the box provided above.
40.6 kJ
mol
Specific Heat & Heats of Fusion & Vap
«grade»
Grade:
«subject»
Subject:
«date»
Date:
1
For specific heat problems, if you are given mass and J
(joules), what will the find be?
A
ΔT
B
mol
C
J
D
g
For specific heat problems, if you are given mass and ΔT,
what will the find be?
2
A
ΔT
B
J
C
g
D
mol
For Specific Heat problems, if you are asked to find ΔT what
information must you be given to be able to solve the
problem? (there may be more than one correct answer,
choose all that apply, or none)
3
A
J
B
ΔT
C
g
D
mol
E
all of these are needed
F
none of these are needed
4
For heat of vaporization problems, if you are given grams of He,
what will you need to do to solve the problem?
A
use specific heat and solve for kJ
B
change grams to moles and use heat of fusion to solve the
problem
C
change grams to moles and use heat of vaporization to solve the
problem
D
you cannot solve this problem
Group practice - work in groups of 4. Copy the questions as given & find, and
work out the answers using a series of fractions.
Q#
J
ΔT
mass
Both are
H2O
1
find
4.5 kg
0°C ---> 22°C
2
25.0 J
find
-60°C ---> -25°C
Q#
mol
substance
kJ
(Chart p. 502)
3
2.50
find
water
vaporization
4
find
44.0
ammonia (NH3
fusion
ANSWERS
1. 414,000 J
2. 0.356g
mol
3. 102 kJ
4. 7.8
5/2/2013 Standards: 7 (Chemical Thermodynamics)
Objectives:
● Students will be able to calculate 2 problem types:
a. specific heat problems
b. heats of vaporization or fusion
DO NOW:
1. When HW papers returned, trade papers for grading.
HOMEWORK:
1. Zum Heating Curve Questions 13-17 (bottom right) (5 pts) Std 7
2. Help Sheet for Mini Quiz Ch 16.1-16.3 (5pts) Std 7
===========================================================
BASKET: ● Journal 5/1 (What you learned, or relearned about
specific heat calcs and heats of vaporization and fusion)
1. Ch 16.2 p. 498 Ch 16.3 #12 & 13; p. 504 20, 21, 22 (5 pts) Std 7
(students will grade each others homework tomorrow)5
Announcement
quiz on
a. specific heat problems
b. heats of vaporization or fusion
Tomorrow, Friday (5/3)
Homework answers for Th 5/2
for substance X
13.
heat of vaporization
heat of
fusion
14.
15.
16.
17.
vaporization = 22 x fusion
melt 10.0 g of X = 0.48 kJ
vap 27 10.0 g of X = 27 kJ
848 J melts
11.5 g H2O
3,020 J vaporizes 11.5 g H2O
fuse 25.og H2O = 8.37 kJ
vap 37.5g H2O = 84.4 kJ
warm H2O 55.2g 0 ---> 100°C 23.1 kJ
cool 10.0g H2O from 200°C ---> 100°C =
2.03 kJ
condense 10.0g H2O =
22.50 kJ
cool 10.0g H2O from 100°C ------> 0°C =
4.18 kJ
freeze 10.0g H2O =
3.34 kJ
cool 10.0g H2O from 0°C ------> -5.0°C =
1.03 kJ
------------total energy removed from 10 g H2O going
from 200°C --> -5.0°C
32.08 kJ
5/3/2013 Standards: 7 (Chemical Thermodynamics)
Objectives:
● Check for understanding of:
a. specific heat problems
b. heats of vaporization or fusion
DO NOW:
1. Prep. for Ch 16 Mini Quiz Ch 16.1, 16.2, 16.3 - polish your Help Sheet
HOMEWORK:
NONE
===========================================================
BASKET: ● Journal 5/2 (What you learned, or relearned about
heat calcs and heats of vaporization and fusion)
1. Zum Heating Curve Questions 13-17 (bottom right) (5 pts) Std 7
For this period only, if you didn't do the
homework last night, or didn't complete
it, you may redo and turn in on Mon for
full credit.
Put papers into 5 stacks
Help Sheets
scratch
The following in order with
smallest # on top:
quizzes
scantron
charts
Spread so #'s show
ΔH = - 50kJ
°C
β
α
Ω
Δ
♂
↓ ↑
♀
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