A student investigated the temperature change during the reaction between malic acid and sodium hydrogencarbonate solution.
Table 1 shows some of the student's results:
| Mass of malic acid added in g\text{g}g | Temperature of solution in ∘C\text{}^\circ\text{C}∘C |
|---|---|
| 0.00 | 22.0 |
| 0.25 | 21.5 |
| 0.50 | 21.0 |
| 0.75 | 20.5 |
| 1.00 | 20.0 |
Explain how the results in Table 1 show that the reaction is endothermic.
The first five data points in Table 1 lie on a straight line of best fit represented by: T=−2.0m+22.0T = -2.0m + 22.0T=−2.0m+22.0 where TTT is the temperature in ∘C\text{}^\circ\text{C}∘C and mmm is the mass of malic acid added in g\text{g}g.
For higher masses of malic acid, the reaction is complete, and the mixture begins to warm up. The line of best fit for these points is represented by: T=0.4m+19.0T = 0.4m + 19.0T=0.4m+19.0
Determine the overall temperature change for this reaction.