Heat combustion of Alcohol

Concentration of an alcohol is related to the number of moles per decimetre cubed of the substance. The more concentrated the substance the more the substance will burn thus more heat energy is given out.

Research Question

Will increasing the concentration of ethanol affect the heat of combustion of the alcohol?

Hypothesis

It is hypothesised that increasing the concentration of ethanol will increase the heat of combustion of the alcohol.

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Variables

Independent

The concentration of ethanol (Molar)

• 0.5 Molar ethanol
• 1.0 Molar ethanol
• 1.5 Molar ethanol
• 2.0 Molar ethanol
• 2.5 Molar ethanol

Dependent

• Heat combustion of the alcohol (°C)

Controlled

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Materials

• 3 L of water
• 200 mL of 0.5 Molar ethanol in beaker

• 200 mL of 1.0 Molar ethanol in beaker
• 200 mL of 1.5 Molar ethanol in beaker
• 200 mL of 2.0 Molar ethanol in beaker
• 200 mL of 2.5 Molar ethanol in beaker
• Bottle containing 800 mL of Distilled water
• 15 × 150 mL Conical flask
• 1 × Metal clamp
• 1 × Wooden tongs

• 1 × Retort stand

• 15 × Spirit burner
• 1 × Thermometer                (± 0.01 °C)
• 1 × Match box
• 1 × Electronic scale                 (± 0.02 g)
• 1 × Permanent pen
• 5 × Label stickers

Method

Drawing up data tables

Getting apparatus ready

1. Set up the electronic scale and attach the metal clamp to the retort stand
2. Using the label stickers and permanent pen, label the beakers that contain the different molar concentration of ethanol accordingly – 0.5; 1.0; 1.5; 2.0; 2.5
3. Label the beaker containing water
4. Using the distilled water, thoroughly clean out the conical flasks and measuring cylinders

Carrying out experiment

1. During the experiment, record any smell or colour of alcohol and any observation in the Qualitative Data table
2. Fill the conical flask with 100mL of water.
3. Place the thermometer inside the conical flask and record the initial temperature of the water
4. Keep the thermometer inside the conical flask
5. Clamp the flask at a height approximately 2cm from where the spirit burner will be placed below
6. Fill the spirit burner with just enough 0.5 Molar of ethanol so that the wick is half soaked in alcohol
7. Weigh the spirit burner attached with the lid containing the alcohol and record the initial mass
8. Place the spirit burner under the conical flask and use the matched to light the wick
9. When the water temperature reaches approximately 40°C, blow out and extinguish the flame
10. Record the exact temperature reached when flames were extinguished
11. Using the tongs, move the spirit burner and lid to the electronic scale and weigh the final mass
12. Dispose the water and alcohol inside the spirit burner
13. Repeat steps 1 – 11, but change the type of ethanol in respect to independent variables 1.0 Molar, 1.5 Molar, 2.0 Molar  and 2.5 Molar of ethanol
14. When repeating steps 1 – 11, make sure a new conical flask and water is used and also a new spirit burner is used
15. When all five experiments of the different molar concentration of ethanol is completed, repeat the experiment another two times for each molar concentration of ethanol in reference to the data table

Calculations

1. Final temp – Initial temp = Temp change (°C)
2. Final mass – Initial mass = Mass used (g)