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A student performed a trial investigation to determine the quantitative relationship between heat of combustion and molar mass of alkanols - HSC - SSCE Chemistry - Question 22 - 2060 - Paper 1
Question 22
A student performed a trial investigation to determine the quantitative relationship between heat of combustion and molar mass of alkanols. The student did this by b... show full transcript
Worked Solution & Example Answer:A student performed a trial investigation to determine the quantitative relationship between heat of combustion and molar mass of alkanols - HSC - SSCE Chemistry - Question 22 - 2060 - Paper 1
Step 1
Graph the calculated and theoretical heat of combustion
Answer
To complete this part, draw a graph with molar mass (g mol⁻¹) on the x-axis and heat of combustion (kJ mol⁻¹) on the y-axis. Ensure to plot the calculated data points corresponding to the given values in the table. Then, overlay the theoretical values by plotting points according to the second column in the table. Use a different color or symbol for each dataset, and add a legend to distinguish between them. Finally, draw lines of best fit for both datasets to visualize the relationship.
Step 2
Discuss the validity of the student's investigation
Answer
The student's investigation is valid as it seeks to establish a relationship between heat of combustion and molar mass using empirical data. It identifies clear experimental conditions and comparative values.
However, there may be sources of systematic error due to variations in experimental setup, such as impurities in the alkanols, environmental conditions affecting combustion, or inaccuracies in measuring heat transfer to water. Additionally, the investigation compares calculated values to theoretical predictions, which provides insight into shortcomings in model accuracy but doesn't account for real-world discrepancies.
Overall, while the approach is sound, the limitations and variabilities in measurements could affect the reliability of conclusions drawn.