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A student performed an experiment to compare the energy content of dry broad beans and dry soybeans - VCE - SSCE Chemistry - Question 8 - 2023 - Paper 1
Question 8
A student performed an experiment to compare the energy content of dry broad beans and dry soybeans. The student followed the method below. 1. Fill a 2 L beaker wit... show full transcript
Worked Solution & Example Answer:A student performed an experiment to compare the energy content of dry broad beans and dry soybeans - VCE - SSCE Chemistry - Question 8 - 2023 - Paper 1
Step 1
Energy content calculation
Answer
To calculate the energy content of the dry broad beans, we use the formula:
Given:
- Mass of the water (m) = 300.0 mL x 0.997 g/mL = 299.1 g
- Specific heat capacity of water (c) = 4.18 J/g°C
- Change in temperature (ΔT) = (final temperature - initial temperature)
Assuming the initial temperature of the water is 25 °C and it rises to 45 °C, ΔT = 45 °C - 25 °C = 20 °C. Thus,
The energy content can then be calculated per 100 g (where the mass of the beans is also considered).
Step 2
Justifiable error analysis
Answer
A possible error that could arise is not accounting for the heat loss to the surrounding environment during the experiment. This might lead to a higher-than-expected energy calculation since the data collected could indicate a rise in water temperature when the heat was actually lost, resulting in inaccurate measurements.
Step 3
Improvement suggestion
Answer
An improvement could be to ensure better insulation was used on the outside of the can. This would allow for more energy to be effectively transferred to the water and thus provide a more accurate change in temperature (ΔT) and a final energy content that would be closer to the true value.
Step 4
Comparison between energy contents
Answer
The energy content of dry soybeans is generally higher than that of dry broad beans. A typical correct response would state that the higher energy content may be attributed to the differing compositions of the beans, including factors like fat and protein content, which can provide more energy upon combustion.