~Ctn,llY 1
microwave with short bursts until it reaches
80 °C.
lieat Capacity of the Calorimeter
• Measur: 50
.nd e .O ml of water with a graduated
CYii
th er and pour into the inner foam cup of
e calorimeter. This will be the cold water.
2
• Place the foam
cup With the cold
Water inside the
beaker.
6. Measure 50.0 ml of the hot water with a
graduated cylinder. Place a thermometer
in the cylinder and gently stir to get a
constant reading. The temperature should be
75-80 °C. Record this as the temperature of
the hot water (TJin Data Table 1.
Remember that 1 ml
of water = 1 g of water.
7.
3. Stir the water with the thermometer until
temperature is constant and record it as the
initial temperature of the cold water (TJ in
Data Table 1.
A
W
Quickly pour the 50.0 ml of hot water
into the cold water and start a timer.
8. Gently stir the mixed water with the
thermometer, and record the temperature at
1 minute and then at 1-minute intervals for
10 minutes in Data Table 1.
4. Fill a third foam cup ¾ full with the hottest tap
9. Discard the water, dry the cup with a paper
water possible.
towel, and place it back in the calorimeter.
5. Take the temperature of the hot water. If the
temperature is less than 80 °c, heat in a
10.Repeat this activity, and collect a second set
of data.
Data Table 1: The Heat Capacity of the Calorimeter
Time Trial 1
Trial2
(min) Temp. 0 c Temp. °C
1
2
Trial 1 Trial 2
Initial temperature of cold water, Tc
L\1
Initial temperature of warm water, Th
3
Temperature at time 0 from graph, T
j&t
4
Heat lost by hot water L1 ·1'6
"q
= C x L\T x m
-:::
Ll (hot water)
7
1
l
0
l
Q0(
Jt~ ::DA')
,
--I
.
.:. -
---i r1 :
1\VJJ
-
Heat gained by cold water l I.Ill J,lc;c '3 5fJl
Liq(coldwater) = C x L\T x m 1 - -=-. ·"'\) -c - c..._
.J
5
6
continued on next page
1°
,;
~\'So - )0
/ II
7 L
Heat gained by calorimeter in J
Liq{cal) = ILiq(hot water) + Liq(cold wate~I
J
1
8
l-1 \0
9
~-' \
.,
0
()\)
/l_/\ v
J
\
L__~::..+-'---'------
8 Caronna Distance Leaming
-\
-J
l,iJ-6 -
5m 55-15
f'L--Q f\
S
\j7
__i
DiiL" _:_
- _!__
/7. --:c: ~ .' -:-;-~1 ,:J
~=\,_r7'-J-:-:1
'- \ii
. \
Heat capacity (C) of the calpr~meter in~l°C
Ccal = L\q(caQ / LiTcal
L tr-, /tJ . ,
Average heat capacity (C) of calorimeter in J/oc
j/
c\,,cf, '.J
1
• {l
~5
.J\
~
VJ I
I-,.;/i~T
O
C_
,. cal~=~T~-~T
~--+--.------i-c::::r---:~
_ f1.
1
1
/}rf?A r
Temperature change of\the cal?rimeter
,
\
.. \
I -.
:j-'
0 11}{;-.
-7D') ~) -:: - 7'-Y
,i,,
tO
cv:~ - L.\. \
L\. \tJ/(J)l '--~-15 ;JJ -
.j
ACTIVITY
ACTIVITV 4
ACTMTY 3 continued
7. Repeat steps 1-6 with 10.0 g and 15.0 g of
NH4 CI.
8. For all trials in activities 2 and 3, calculate the
following and record in Data Table 2:
9. Moles of Salts
Moles = mass/molar mass
molar mass CaCl2 = 110.98 g/mol
molar mass NH4CI = 53.49 g/mol
0
10.Change in temperature ( C)
Lff = T1 -T;
11. Heat absorbed by the solution (J)
cw = 4.18 (J/g)°C
qw = -[cw X mW X Lil]
12. Heat absorbed by the calorimeter (J)
qcal = -[Ccal X Lill
13. Enthalpy of solution (J)
LiH = qw + qca1
14.Enthalpy of solution (kJ)
LlH (kJ) = LiH/1 000
15. Enthalpy/mole of solution
(kJ/mol)
LlH = LlH (kJ) / moles of salt
501
fJ
1-1ot p9ol<
osal tor a
Design a pr~:ol<
cafciul11
and a cold
-r: ble 2 tor
-,,e
I
· oata ,a
deterf11
Based on the data~~iurll chloride\ QLlantitY 8
111 a1<e
chloride and arnrn
e and wna
und to us
ded to
cl<S
0
which cornP
ill be nee
eot11 pa
of each compound wd cold pacl<-_ 100 g of
. I hot pack an
eel on usin9
,,d the
chemIca
t d bas
60 °C, a
rri
should be caicula : should reach oC frorfl a roo
water. The hot pac o down to 3.0
ack should g
co Id P
5
I
temperature of 2
.
pll for c;aC 2
heet and gra
a,cis and
create a spreads ,,,ass on tile ,c-_ for
1·11
NH Cl. p1ot the
tile y-a:,(IS
and
"
ture on
llan9e
change in tempera
will be tile c ed
both graphs- fhe ::eof salt dissol" .
9
temperature per
oc
Hot pack: compoun nee
to achieve 60 °C:
,_...,,.,.....
\
.
100 g of water. - - -
Grams needed per
Cold Pack: compound r.i ed
to achieve 3.0 °C: j~01=:µA-- - -- - er 1oo g of water: - Grams needed P
16.Average enthalpy/mole of solution (kJ/mol),
you will have 1 average for your CaCl2 trials
and another for your NHPI trials.
\ff)l,:.
\5
Q: rn c_ D\
0-==- \\OJ"))_L\ Ii4)l
continued on next page
1O Carolina Distance Learning
CAQUII