Starter quiz
Name the alcohol shown in the image- 'butanol' ✓
- What hazard symbol would you expect to find on an alcohol burner in the lab?
- flammable ✓
- radioactive
- compressed gas
- harmless
- explosive
-
- Which variable is defined as the single variant that is changed in an investigation.
- dependent variable
- independent variable ✓
- control variable
-
- What is the molecular formula of propanol?
- C₃H₇OH ✓
- C₃H₈O
- C₃H9O
- C₂H₇O
- C₂H₈O
-
- In a calorimetry experiment the initial temperature of water is 23ᵒC. The water temperature rises to 55ᵒC. What is the temperature change?
- 22
- 23
- 32 ✓
- 54
- 55
-
- What number needs to be placed in front of the CO₂ to balance this equation? C₄H₉OH + 6O₂ → _CO₂ + 5H₂O.
- 1
- 2
- 3
- 4 ✓
-
Exit quiz
- Which of the following statements about the combustion of alcohols are true?
- The longer the carbon chain in an alcohol, the more energy is released. ✓
- The longer the carbon chain in an alcohol, the less energy is released.
- Butanol has a longer carbon chain than methanol. ✓
- Butanol has a shorter carbon chain than methanol.
-
- What is the name of an experiment that can be used to measure the energy released from a fuel such as alcohol?
- 'calorimetry' ✓
- 2 g of methanol, ethanol and propanol were combusted in a calorimetry experiment. Which fuel will cause the greatest temperature rise in 50 cm³ of water in the calorimeter?
- methanol
- ethanol
- propanol ✓
-
- Using the data of the mass needed to cause a temperature rise. Which alcohol releases the most energy during combustion?
- methanol 0.043 g/°C
- ethanol 0.041 g/°C
- propanol 0.037 g/°C ✓
-
- Calculate the mass of butanol needed to produce a 1°C temperature rise when 1.3 g of butanol produced a 49°C rise in temperature of 100 cm³ of water.
- 63.7 g
- 37.69 g
- 0.027 g ✓
- 0.77 g
-
- Calculate the mass of propanol needed to produce a 10°C temperature rise when 1.45 g of propanol produced a 46°C rise in temperature of 100 cm³ of water.
- 0.021 g
- 0.21 g
- 0.0315 g
- 0.315 g ✓
- 69 g
-
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- Calorimetry can be used to measure a reaction's energy change indirectly.
- Calorimetry data can be used to calculate the mass of alcohol needed to cause a 1°C rise in temperature of the water.
- An alcohol that causes a 1°C temperature rise when the least amount is combusted is releasing the most energy.
- The energy change of combustion for a variety of alcohols can be compared to the molecular formula of each alcohol.
Common misconception
Forgetting to measure the initial mass of the burner and initial temperature of the water.
Emphasise the importance in remembering to measure this data when writing a method for this practical.
Keywords
Alcohols - Alcohols are a homologous series that contain the -OH functional group.
Combustion - Combustion is an exothermic reaction where a substance reacts with oxygen.
Calorimetry - Calorimetry is an experiment that can be used to measure the energy released from a fuel such as alcohol.
Independent variable - The independent variable is the single variant that is changed in an investigation.
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