A student investigated the temperature change when different masses of anhydrous calcium chloride were dissolved in 100 cm3 of water.
Table 1 shows the student's results:
| Mass of calcium chloride added (g\text{g}g) | Highest temperature of solution (∘C^\circ\text{C}∘C) |
|---|---|
| 2.0 | 24.1 |
| 4.0 | 28.2 |
| 6.0 | 32.3 |
| 8.0 | 36.4 |
| 10.0 | 40.5 |
Assuming a linear relationship, calculate the initial temperature of the water (the temperature where the mass of calcium chloride added is 0 g).
The student then repeated the experiment four times with 6.0 g of calcium chloride to check the reliability of the results. Table 2 shows these repeat trials:
| Trial 1 (∘C^\circ\text{C}∘C) | Trial 2 (∘C^\circ\text{C}∘C) | Trial 3 (∘C^\circ\text{C}∘C) | Trial 4 (∘C^\circ\text{C}∘C) |
|---|---|---|---|
| 32.1 | 32.7 | 32.2 | 32.6 |
Calculate the mean highest temperature and express the result with its uncertainty in the form mean±uncertainty\text{mean} \pm \text{uncertainty}mean±uncertainty, where the uncertainty is calculated as half of the range.