Combustion of alcohols: planning | Chemistry | Quizalize & Oak National Academy

Starter quiz

Order the following alcohols by chain length starting with the shortest.

1

⇔

methanol

2

⇔

ethanol

3

⇔

propanol

4

⇔

butanol

5

⇔

pentanol
What is the name of the alcohol shown in the image?

'ethanol' ✓
Which is the molecular formula of propanol?

C₂H₆O

C₃H₈O ✓

C₃H₇OH ✓

C₂H₅OH

C₃H₇COOH
Which alcohol has the formula C₄H₉OH?

butanol ✓

ethanol

pentanol

methanol

propanol
What are the products from the complete combustion of butanol?

oxygen

methanol

hydrogen

carbon dioxide ✓

water ✓
Match the variable to the correct definition.

independent

⇔

the variable that you change or select values for ✓

dependent

⇔

the variable that you measure or observe to get your results ✓

control

⇔

variables that must remain the same throughout an investigation ✓

Exit quiz

What is calorimetry?

an experiment to measure the volume of acid needed to neutralise an alkali

an experiment that can be used to measure the energy released from a fuel ✓

an experiment to produce pure, dry salt crystals

an experiment to measure the mass of dissolved salts in a water sample
When using calorimetry to investigate whether the type of alcohol combusted affects the energy given out. The temperature rise is which type of variable?

independent variable

dependent variable ✓

control variable
When using calorimetry to investigate whether the type of alcohol combusted affects the energy given out, the volume of water in the calorimeter is an example of which variable?

independent variable

dependent variable

control variable ✓
Which of the following are ways to reduce heat loss to the surroundings when conducting calorimetry?

add a heatproof mat below the alcohol burner

add draught screens ✓

open the classroom window

add a lid to the calorimeter ✓
Which of the following need to be measured when carrying out calorimetry to indirectly measure the energy released from a fuel?

inital mass of alcohol burner ✓

final mass of alcohol burner ✓

time taken for the water to change temperature

initial temperature of the water ✓

initial mass of the calorimeter
Which is the correct balanced equation for the complete combustion of ethanol?

C₂H₅OH + 3O₂ → 6CO₂ + 3H₂O

C₂H₅OH + 3O₂ → 2CO₂ + 4H₂O

C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O ✓

Worksheet

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Lesson Details

Key learning points

Balanced symbol equations can be written for the combustion of alcohols.
It is difficult to measure directly the energy change of a reaction.
Calorimetry can be used to measure a reaction's energy change indirectly.

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

Energy change - The energy change is the difference between the energy of the reactants and the energy of the products.
Calorimetry - Calorimetry is an experiment that can be used to measure the energy released from a fuel such as alcohol.
Molecular formula - The molecular formula shows the actual number of atoms of each element in a molecule of a compound.
Combustion - Combustion is an exothermic reaction where a substance reacts with oxygen.
Alcohols - Alcohols are a homologous series that contain the -OH functional group.