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preiou5
original_c.docxOriginal work
1.Graph the data points using an Excel spreadsheet; time in seconds on the x-axis and
temperature on the y-axis. The graph should look similar to the sample cooling curve below.
2. Place a ruler on the declining temperature portion of the curve and extrapolate to the 0-line.
Read the extrapolated temperature where the straight line intersects the 0-time line. This
temperature represents the final temperature of the mixture. Enter this temperature in Data
|
Data Table 1: Sample data |
|
|
Initial Temperature of HCl - oC |
25.1 |
|
Initial Temperature NaOH - oC |
24.8 |
|
Average Initial Temperature - oC |
24.95 |
|
Final Temperature of mixture (extrapolated) |
|
|
Change in Temperature of mixture, ΔT |
|
|
Data Table 2: Sample data |
|
|
Time after mixing- seconds |
Temperature - °C |
|
20 |
36.6 |
|
40 |
35.9 |
|
60 |
35.8 |
|
80 |
35.8 |
|
100 |
35.7 |
|
120 |
35.7 |
|
140 |
35.6 |
|
160 |
35.5 |
|
180 |
35.5 |
|
200 |
35.4 |
|
220 |
35.3 |
|
240 |
35.2 |
|
260 |
35.1 |
|
280 |
34.9 |
|
300 |
34.8 |
Part 2: Reaction 2: NH4Cl + NaOH → NH3 + NaCl + H2O
|
Data Table 3: |
|
|
Initial Temperature of NaOH - oC |
24.8 |
|
Initial Temperature NH Cl - oC 4 |
26.6 |
|
Average Initial Temperature - oC |
25.7 |
|
Final Temperature of mixture (extrapolated) |
|
|
Change in Temperature of mixture, ΔT |
|
94
©Hands-On Labs, Inc.
www.LabPaq.com
|
Data Table 4: |
|
|
Time after mixing- seconds |
Temperature - oC |
|
20 |
25.5 |
|
40 |
25.4 |
|
60 |
25.3 |
|
80 |
25.2 |
|
100 |
25.2 |
|
120 |
25.2 |
|
140 |
25.2 |
|
160 |
25.2 |
|
180 |
25.1 |
|
200 |
25.1 |
|
220 |
25.1 |
|
240 |
25.1 |
|
260 |
25.0 |
|
280 |
25.0 |
|
300 |
25.0 |
Part 3: Reaction : NH3 + HCl → NH4Cl
|
Data Table 5: |
|
|
Initial Temperature of HCl - oC |
25.1 |
|
Initial Temperature NH - oC 3 |
25.0 |
|
Average Initial Temperature - oC |
25.05 |
|
Final Temperature of mixture (extrapolated) |
|
|
Change in Temperature of mixture, ΔT |
|
96
©Hands-On Labs, Inc.
www.LabPaq.com
|
Data Table 6: |
|
|
Time after mixing- seconds |
Temperature - oC |
|
20 |
33.0 |
|
40 |
33.0 |
|
60 |
32.9 |
|
80 |
32.8 |
|
100 |
32.7 |
|
120 |
32.6 |
|
140 |
32.5 |
|
160 |
32.3 |
|
180 |
32.2 |
|
200 |
32.1 |
|
220 |
32.0 |
|
240 |
31.9 |
|
260 |
31.8 |
|
280 |
31.7 |
|
300 |
31.6 |
Questions
For A. & B. See the calculations for the Data Tables above.
A. Using the data from your data tables calculate ΔT for all three reactions:
B. Calculate the heat loss or gain of the three solution mixtures:
