Vernier Software & Technology

# Energy Content of Fuels

## Introduction

In this experiment, you will find and compare the heat of combustion of two different fuels: paraffin wax and ethanol. Paraffin is a member of a group of compounds called alkanes that are composed entirely of carbon and hydrogen atoms. Many alkanes, such as gasoline and diesel oil, are important fuels. Ethanol, C2H5OH, is used as a gasoline additive (gasohol) and as a gasoline substitute. In this experiment, you will compare the energy content of paraffin and ethanol by measuring their heats of combustion in kJ/g of fuel.

In order to find the heat of combustion, you will first use the energy from burning ethanol or paraffin to heat a known quantity of water. By monitoring the temperature of the water, you can find the amount of heat transferred to it, using the formula

$q = C_p \cdot m \cdot \Delta t$

where q is heat, Cp is the specific heat capacity of water, m is the mass of water, and Δt is the change in temperature of the water. Finally, the amount of fuel burned will be taken into account by calculating the heat per gram of fuel consumed in the combustion.

## Objectives

In this experiment, you will

• Compare the heat of combustion for paraffin wax and ethanol.
• Calculate the heat of combustion and percent efficiency for both fuels.

## Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

### Option 2

You may also need an interface and software for data collection. What do I need for data collection?

## Chemistry with Vernier

See other experiments from the lab book.

 1 Endothermic and Exothermic Reactions 2 Freezing and Melting of Water 3 Another Look at Freezing Temperature 4 Heat of Fusion of Ice 5 Find the Relationship: An Exercise in Graphing Analysis 6 Boyle's Law: Pressure-Volume Relationship in Gases 7 Pressure-Temperature Relationship in Gases 8 Fractional Distillation 9 Evaporation and Intermolecular Attractions 10 Vapor Pressure of Liquids 11 Determining the Concentration of a Solution: Beer's Law 12 Effect of Temperature on Solubility of a Salt 13 Properties of Solutions: Electrolytes and Non-Electrolytes 14 Conductivity of Solutions: The Effect of Concentration 15 Using Freezing Point Depression to Find Molecular Weight 16 Energy Content of Foods 17 Energy Content of Fuels 18 Additivity of Heats of Reaction: Hess's Law 19 Heat of Combustion: Magnesium 20 Chemical Equilibrium: Finding a Constant, Kc 21 Household Acids and Bases 22 Acid Rain 23 Titration Curves of Strong and Weak Acids and Bases 24 Acid-Base Titration 25 Titration of a Diprotic Acid: Identifying an Unknown 26 Using Conductivity to Find an Equivalence Point 27 Acid Dissociation Constant, Ka 28 Establishing a Table of Reduction Potentials: Micro-Voltaic Cells 29 Lead Storage Batteries 30 Rate Law Determination of the Crystal Violet Reaction 31 Time-Release Vitamin C Tablets 32 The Buffer in Lemonade 33 Determining the Free Chlorine Content of Swimming Pool Water 34 Determining the Quantity of Iron in a Vitamin Tablet 35 Determining the Phosphoric Acid Content in Soft Drinks 36 Microscale Acid-Base Titration

### Experiment 17 from Chemistry with Vernier Lab Book

#### Included in the Lab Book

Vernier lab books include word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.