A student is conducting an investigation to determine the optimal conditions for the production of biodiesel from canola oil through transesterification. The student varies the catalyst concentration (NaOH) and reaction temperature, measuring the yield of biodiesel using gas chromatography-mass spectrometry (GC-MS). After conducting several trials, the student notices significant variability in the biodiesel yield for trials conducted at the same catalyst concentration and temperature.
Discuss three limitations of the student’s investigation methodology and/or methods that could contribute to the observed variability in biodiesel yield. For each limitation, explain how it could specifically impact the accuracy and precision of the results.
Marking your answer...
This may take a few seconds
Sign up for free to see your full marking breakdown and personalised study recommendations.
Create Free Account Log inThis is a free VCE Units 3 & 4 Chemistry practice question worth 6 marks, testing your understanding of Investigation limits. It falls under Student-designed scientific investigation in Unit 4: How are carbon-based compounds designed for purpose?. Submit your answer above to receive instant AI-powered marking and personalised feedback.
Carbon is the basis not only of the structure of living tissues but is also found in fuels, foods, medicines, polymers and many other materials that we use in everyday life. In this unit students investigate the structures and reactions of carbon-based organic compounds, including considering how green chemistry principles are applied in the production of synthetic organic compounds. They study the metabolism of food and the action of medicines in the body. They explore how laboratory analysis and various instrumentation techniques can be applied to analyse organic compounds in order to identify them and to ensure product purity. Students conduct practical investigations related to the synthesis and analysis of organic compounds, involving reaction pathways, organic synthesis, identification of functional groups, direct redox titrations, solvent extraction and distillations. Throughout the unit students use chemistry terminology including symbols, formulas, chemical nomenclature and equations to represent and explain observations and data from their own investigations and to evaluate the chemistry-based claims of others. A student-designed scientific investigation involving the generation of primary data related to the production of energy and/or chemicals and/or the analysis or synthesis of organic compounds is undertaken in either Unit 3 or Unit 4, or across both Units 3 and 4, and is assessed in Unit 4 Outcome 3. The design, analysis and findings of the investigation are presented in a scientific poster format. School-based assessment The student’s level of achievement in Unit 4 will be determined by School-assessed Coursework, which contributes 30 per cent to the study score. Students complete a set of tasks to address Outcomes 1 and 2, and design and conduct a student investigation for Outcome 3. External assessment The level of achievement for Units 3 and 4 is also assessed by an end-of-year examination contributing 50 per cent to the study score.
Students undertake a student-designed scientific investigation in either Unit 3 or Unit 4, or across both Units 3 and 4. The investigation involves the generation of primary data related to the production of energy and/or chemicals and/or the analysis or synthesis of organic compounds. The design, analysis and findings are presented in a scientific poster. Outcome 3 On completion of this unit the student should be able to design and conduct a scientific investigation related to the production of energy and/or chemicals and/or the analysis or synthesis of organic compounds, and present an aim, methodology and method, results, discussion and conclusion in a scientific poster. Key knowledge
the limitations of investigation methodologies and methods, and of data generation and/or analysis
All free, all instant AI marking.
A student investigates the enthalpy change ($\Delta H$) of the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH) using ca…
A student is designing an experiment to determine the concentration of ethanoic acid in vinegar using titration with a standardized solution…
A student is investigating the effect of temperature on the rate of an enzyme-catalyzed reaction using spectrophotometry to measure product…
A student is investigating the rate of the reaction between acidified potassium permanganate ($KMnO_4$) and oxalic acid ($H_2C_2O_4$). The s…
A student is investigating the rate of the reaction between ethanol and ethanoic acid to produce ethyl ethanoate and water, using sulfuric a…
A student designs an experiment to investigate the effect of temperature on the rate of an enzyme-catalyzed reaction. Which of the following…
StudyPulse has thousands of VCE Chemistry questions with full AI feedback, mark breakdowns, progress tracking, and study notes across every Key Knowledge point including Investigation limits.
