- Add 50 cm^3 of distilled water to a polystyrene cup.
- Measure the steady temperature of the water.
- Add a sample of ammonium nitrate to the polystyrene cup, with stirring.
- Measure the final temperature of the water.
Question:
The dissolving process of this type may be slow and heat may be lost while the process is still going on. This can make it difficult to get an accurate measurement of the temperature change in the method above. Suggest how, using a clock and a graph paper, the method can be modified to find the maximum temperature change more accurately. [4 marks]
更新1:
Do you mean, at exactly 3 minutes, when we add the NH4NO3 into the cup, there is a temperature change(maximum) but we cannot determine it experimentally due to heat loss... So we need to use this method to extrapolate the temperature change at 3 minutes (the time when we add NH4NO3)?
