Two students decided to investigate the effect of water and air on iron object under identical experimental conditions. They measured the mass of each object before placing it partially immersed in 10 ml of water. After a few days, the object were removed, dried and their masses were measured. The table shows their results.
| Student | Object |
Mass of Object before Rusting in g |
Mass of the coated object in g |
| A | Nail | 3.0 | 3.15 |
| B | Thin plate | 6.0 | 6.33 |
(a) What might be the reason for the varied observations of the two students?
Answer:
a)
- Rusting occurs in both A and B so there is an increase in mass due to the formation of rust .
- As the surface area of B is more , more of B is exposed to air and water.
- Hence, the extent of rusting in B is more.
