Cambridge Secondary (7-9). Stage 8. Science. Learner's Book - Unit 8: Chemical reactions - Question 98

Zara and Arun are carrying out an investigation into the heat given off when they add pieces of calcium to water. They both use 10 cm³ water and add pieces of calcium.

These are Zara’s results.

| Mass of calcium added in g | Start temperature in °C | Final temperature in °C | Temperature change in °C |
|---|---|---|---|
| 1 | 19 | 20 | … |
| 2 | 19 | 21 | … |
| 3 | 19 | 22 | … |
| 4 | 19 | 23 | … |

These are Arun’s results.

| Mass of calcium added in g | Start temperature in °C | Final temperature in °C | Temperature change in °C |
|---|---|---|---|
| 1 | 21 | 22 | … |
| 2 | 21 | 22 | … |
| 3 | 21 | 24 | … |
| 4 | 21 | 25 | … |

What trend is shown by both sets of results? [1]