Vernier Software & Technology

# Endothermic and Exothermic Reactions

## Introduction

Some chemical reactions absorb energy and are called endothermic reactions. Many chemical reactions give off energy. Chemical reactions that release energy are called exothermic reactions. You will study one endothermic reaction and one exothermic reaction in this experiment.

In Part I, you will study the reaction between citric acid solution and baking soda. An equation for the reaction is

${{\text{H}}_{\text{3}}}{{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{{\text{O}}_{\text{7}}}{\text{(aq) + 3 NaHC}}{{\text{O}}_{\text{3}}}{\text{(s)}} \to {\text{3 C}}{{\text{O}}_{\text{2}}}{\text{(g) + 3 }}{{\text{H}}_{\text{2}}}{\text{O(l) + N}}{{\text{a}}_{\text{3}}}{{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{{\text{O}}_{\text{7}}}{\text{(aq)}}$

In Part II, you will study the reaction between magnesium metal and hydrochloric acid. An equation for this reaction is

${\text{Mg(s) + 2 HCl(aq)}} \to {{\text{H}}_{\text{2}}}{\text{(g) + MgC}}{{\text{l}}_{\text{2}}}{\text{(aq)}}$

## Objectives

In this experiment, you will

• Observe two chemical reactions.
• Measure temperature changes.
• Determine the change in temperature, Δt, for each of the reactions.
• Identify endothermic and exothermic reactions.

## 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?

## Physical Science with Vernier

See other experiments from the lab book.

 1 Temperature Probe Response Time 2 Boiling Temperature of Water 3 Freezing and Melting of Water 4 Evaporation of Alcohols 5 Endothermic and Exothermic Reactions 6 Neutralization Reactions 7 Mixing Warm and Cold Water 8 Heat of Fusion 9 Energy Content of Fuels 10 Energy Content of Foods 11 Absorption of Radiant Energy 12 An Insulated Cola Bottle 13 A Good Sock 14 Insolation Angle 15 Solar Homes and Heat Sinks 16 Conducting Solutions 17 Conductivity of Saltwater: The Effect of Concentration 18 Acid Strengths 19 Frictional Forces 20 First-Class Levers 21 Pulleys 22 An Inclined Plane 23 Reflectivity of Light 24 Polarizing Light 25 How Bright is the Light? 26 Electromagnets: Winding Things Up 27 Magnetic Field Explorations 28 Household Acids and Bases 29 Acid Rain 30 Gas Pressure and Volume 31 Gas Temperature and Pressure 32 Fun with Pressure 33 Lemon "Juice" 34 Simple Circuits 35 Graphing Your Motion 36 Speeding Up 37 It's Race Day 38 Crash Lesson 39 Newton's Second Law 40 Falling Objects

### Experiment 5 from Physical Science 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.