A student investigated the temperature change during the reaction between magnesium ribbon and dilute hydrochloric acid.
Table 1 shows some of the student's results:
| Mass of magnesium added in g\text{g}g | Temperature of solution in ∘C\text{}^\circ\text{C}∘C |
|---|---|
| 0.00 | 18.0 |
| 0.20 | 20.4 |
| 0.40 | 22.8 |
| 0.60 | 25.2 |
| 0.80 | 27.6 |
Explain how the results in Table 1 show that the reaction is exothermic.
The first five data points in Table 1 lie on a straight line of best fit represented by: T=12.0m+18.0T = 12.0m + 18.0T=12.0m+18.0 where TTT is the temperature in ∘C\text{}^\circ\text{C}∘C and mmm is the mass of magnesium added in g\text{g}g.
For higher masses of magnesium, the hydrochloric acid has completely reacted, and the mixture begins to cool down. The line of best fit for these points is represented by: T=−3.0m+31.5T = -3.0m + 31.5T=−3.0m+31.5
Determine the overall temperature change for this reaction.