Energy · Grade 10
Energy from fuels: burning alcohols
ChemAI · Worksheet
NameClassDate
Aim
Heat 100 g of water with a spirit burner, measure ΔT and the mass burnt, and calculate the enthalpy of combustion.
⚠ Alcohols are flammable: keep the bottles away from the flame, put the cap on to put it out.
Before you start: what do you predict will happen? Why?
What you do
| Step | What I observed | |
|---|---|---|
| 1 | Note the water temperature and the mass of the burner, then light the ethanol burner. | |
| 2 | When the water is about 20 °C warmer (speed ×5), put the cap on. Read the new mass. | |
| 3 | Repeat with another alcohol (Fuel, New water). Which releases more energy per mole? | |
| 4 | Calculate the enthalpy of combustion for your last fuel, as a positive number (kJ/mol). |
Calculation
Calculate the enthalpy of combustion for your last fuel, as a positive number (kJ/mol).
Questions
- Write a word or symbol equation for one reaction you observed.
- Explain your most important observation using particles, ions or energy.
- Was your prediction right? What would you change to get a more reliable result?