Exothermic: Thermodynamics and Data Table

766 Words Dec 2nd, 2013 4 Pages
Heidi Duncan
11/24/13
Exothermic and Endothermic Reactions Lab
The purpose of this lab is to observe how heat is released or absorbed with different chemicals.
Data Table 1 – HCI and NaOH

Trial 1
Trial 2
Avg
Volume 1.0 M HCI(ml)
25
25
-
Volume1.0 M NaOH (ml)
25
25
-
Ti of HCI before mixing
20
20
-
Ti of NaOH before mixing(
20
20
-
Average Ti before mixing(
20
20
-
Tf of mixture )
26
26
-
T )
6
6
-
Specific Heat (J/g)
4.184
4.184
-
Heat, q (J)
1255.2
1255.2
1255.2

Data Table 2- NH4 NO3 and H20

Trial 1
Trial 2
Avg
Mass of NH4 NO3 (g)
12
11.93
-
Volume of H20 ( ml)
25
25
-
Ti of H2O )
20
20
-
Tf of mixture )
-3
-2
-
T )
-23
-22
-
Specific Heat(J/g)
4.184
4.184
…show more content…
Record in data table 1. Calculate the average heat (q) by averaging trials 1 and 2. Record in data table 1.
Q=?
M = 50g
S =4.184 J/g
T=26 - 20 = 6
Q=( 50g)(4.184J/g)(6=1255.2J
*Both Trials had the same results
5. Classify the reaction as either exothermic or endothermic. Give evidence for your answer.
-The reaction is exothermic because the temperature rose.

Reaction 2 – NH4 NO3 and H20

1. Calculate the change in temperature (T) for each trial. Record in Data Table 2.
Trial #
Tf
Ti
T
Trial 1
-3
20
-3 -20= -23
Trial 2
-2
20
-2- 20 -22

2. Did the temperature of the water rise or fall when the NH4NO3 was added. Explain this in terms of heat transfer.
-The temperature of the water fell because the NH4NO3 absorbed the heat of the water.
3. Calculate the heat ( q in joules ) for the reaction. Record q for each trial in data table 2.
Trial 1
Trial 2
Avg
Q = ?
Q = ?
Q = ?
M=25g
M=25g
M=25g
S=4.184J/g
S=4.184J/g
S=4.184J/g
T= -3 – 20 =-23
T=-2 -20= -22
T=-22.5
Q= (25g)(4.184)(-23)=
-2405.8j
Q=(25g)(4.184)(-22) =
-2301.2J
Q=(25g)(4.184)(-22.5)=
-2353.5
4.Calculate the heat absorbed or released per gram of solute added to the water (in joules/g) record in data table 2. Calculate the average heat per gram by averaging trials 1 and 2.
Trial 1
Trail 2
Avg
-2405.8J/12g
-2301.2 J / 11.93 g
-2353.5 J /11.965 g
-200 J/g
-193 J/g
-197 J/g
5.Classify the reaction as either exothermic or endothermic. Give evidence for
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