Comparing the Energy Content of Fuels
Integrated Science 3
Redwood High School
Name:
11/12
Per:
n Introduction
You have identified a number of different energy sources that are important to humans – including those used
now and those used more extensively in the past. These different sources have very different energy content values.
The energy content of a substance is the amount of heat produced or given off by the combustion of one gram of
that substance. The energy content, in turn, is critical in how a specific source can be used. For example, burning
one gram of wood yields approximately 2,760 calories of heat, while coal can produce 7,200 calories per gram.
With its greater energy content, coal was able to more efficiently provide the vast amounts of heat needed for the
factories of the Industrial Revolution.
In this lab, you will determine and compare the heat content of different fuels – paraffin wax, denatured alcohol
and kerosene. Paraffin wax and kerosene are products of the distillation of crude oil (petroleum), while denatured
alcohol (ethanol) is produced when bacteria and/or yeast ferment grain products. Paraffin wax is primarily used to
make candles, which still provides the main source of lighting worldwide. Denatured alcohol is often used as a fuel
additive to produce a more efficient, cleaner and cooler-burning fuel. Kerosene is also used as a fuel additive due to
its highly combustible nature, but it is also used for heating, lighting and cooking.
n Procedures
Ø Part 1. Determining the Energy Content of a Liquid Fuel – Denatured Alcohol
1. Using an electronic balance, determine and record the initial mass of the burner and fuel in Data Table 2.
Make all mass measurements to the nearest 0.1gram.
2. Using a graduated cylinder, measure exactly 125 ml of cold water and add it to the beaker. Use the density
of water to determine and record it’s mass in grams in Data Table 2.
3. Set up the calorimeter as demonstrated by your teacher. You may also refer to Fig. 7.6 in the Global
Science textbook. Make adjustments so that the flame from the burner (do not light it yet) will just touch
the bottom of the beaker.
4. Record the initial temperature of the water to the nearest 0.5 ºC in Data Table 2.
5. Light the wick and heat the water until the temperature reaches between 55 and 60 ºC.
6. Stir the water while it is heating. Record final temperature in Data Table 2.
7. Blow out the flame. Determine and record the final mass of the burner and fuel in Data Table 2.
8. Use your data and the equations provided to calculate the energy content of denatured alcohol.
Ø Part 2. Determining the Energy Content of a Solid Fuel – Paraffin Wax
1. Using an electronic balance, determine and record the initial mass of the candle in Data Table 1. Make all
mass measurements to the nearest 0.1gram.
2. Using a graduated cylinder, measure exactly 125 ml of cold water and add it to the beaker. Use the density
of water to determine and record it’s mass in grams in Data Table 1.
• recall: the density of water = 1.0 g/cm3 = 1.0 g/ml
3. Set up the calorimeter as demonstrated by your teacher. You may also refer to Fig. 7.6 in the Global
Science textbook. Make adjustments so that the flame from the candle (do not light it yet) will just touch
the bottom of the beaker.
4. Record the initial temperature of the water to the nearest 0.5 ºC in Data Table 1.
5. Light the candle and heat the water until the temperature reaches between 55 and 60 ºC.
6. Stir the water while it is heating. Record final temperature in Data Table 1.
7. Blow out the flame. Determine and record the final mass of the candle in Data Table 1.
8. Use your data and the equations provided to calculate the energy content of paraffin wax.
Ø Part 3. Determining the Energy Content of a Liquid Fuel – Kerosene
1. Use the data in Data Table 3 and the equations provided, to calculate the energy content of kerosene.
n Data [data from tables 1 and 2 to be recorded in the class data tables]
Data Table 1. Raw Data – Energy Content of Liquid Fuel (Denatured Alcohol)
Your Group’s
Trial
Measurements
Mean Measurement
Values
Initial mass of alcohol (g)
(g)
Final mass of alcohol (g)
(g)
Mass of alcohol burned (g)
(g)
Mass of water (g)
(g)
Initial temp. of water (ºC)
(ºC)
Final temp. of water (ºC)
(ºC)
Temp. change of water (ºC)
(ºC)
Data Table 2. Raw Data – Energy Content of Solid Fuel (Paraffin Wax)
Your Group’s
Trial
Measurements
Mean Measurement
Values
Initial mass of candle (g)
(g)
Final mass of candle (g)
(g)
Mass of candle burned (g)
(g)
Mass of water (g)
(g)
Initial temp. of water (ºC)
(ºC)
Final temp. of water (ºC)
(ºC)
Temp. change of water (ºC)
(ºC)
Data Table 3. Raw Data – Energy Content of Liquid Fuel (Kerosene Demonstration)
Measurements
Initial mass of kerosene (g)
Final mass of kerosene (g)
Mean
Measurement
Values
192.8 (g)
191.4 (g)
Mass of kerosene burned (g)
1.4 (g)
Mass of water (g)
125 (g)
Initial temp. of water (ºC)
27 (ºC)
Final temp. of water (ºC)
56 (ºC)
Temp. change of water (ºC)
29 (ºC)
2
Energy Content Lab
n Calculations
1. Use the equation and space below to calculate the heat energy absorbed by the water for each fuel tested. The
cal
).
specific heat of water is 1 ( g•º
C
heat energy absorbed (cal) = mass of water (g) x Δtemp (º C) x specific heat of water ( g•ºcalC )
Data Table 4. Calculations
– Heat Energy Absorbed (cal)
€
Paraffin Wax
€
Denatured Alcohol
Kerosene
Heat energy absorbed (cal)
2. Use the equation and space below to calculate the energy content per gram for each fuel tested.
heat energy absorbed (cal)
energy content ( cal
) =
g
mass of fuel burned (g)
Data Table 5. Calculations – Energy Content (cal/g)
€
Paraffin Wax
Denatured Alcohol
Kerosene
Energy content (cal/g)
3. Use the equation and space below to calculate the percent error for each fuel tested. Compare your results for
energy content with the accepted values in Data Table 7.
percent error =
experimental value ( calg ) – accepted value ( calg )
accepted value ( calg )
Data Table 6. Calculations – Percent Error (%)
Paraffin Wax
€
Denatured Alcohol
×100
Kerosene
Percent error
Data Table 7. Accepted Energy Content Values of Various Fuels
Energy
Energy
Item
Item
Content
Content
(cal/g)
(cal/g)
Steak (beef)
1,840 Coal
7,200
Drinking Alcohol (80 proof)
2,580 Kerosene
10,800
Bread
2,660 Natural gas
11,000
Wood
2,760 Paraffin wax
11,250
Sugar
4,100 Gasoline
11,530
Rubbing Alcohol
6,400 Uranium-235
20,000,000
3
Energy Content Lab
n Discussion and Conclusions
1. Use Data Table 6 to compare your percent error values for each of the fuels tested.
A) What contributed to your error values?
B) What might explain the differences in error values between the different fuel types?
2. What type of energy resource (perpetual, renewable or non-renewable) is each fuel tested?
a. Ethanol:
b. Paraffin Wax:
c. Kerosene:
3. What is one drawback of using each fuel tested as an energy resource?
n Application
4. Fossil fuels are a commonly used energy resource worldwide. In addition to energy content, why are coal, oil,
and natural gas commonly used energy resources?
5. Uranium-235 has, by far, the largest energy content value of the fuels compared in Data Table 7. Would you
recommend it to be used as a primary energy source for human energy needs? Why or why not?
4
Energy Content Lab