Vernier Software and Technology
Vernier Software & Technology

Heat of Combustion: Magnesium

Figure from experiment 19 from Chemistry with Vernier


In Experiment 18, you learned about the additivity of reaction heats as you confirmed Hess’s law. In this experiment, you will use this principle as you determine a heat of reaction that would be difficult to obtain by direct measurement—the heat of combustion of magnesium ribbon. The reaction is represented by the equation

Cannot create image: {\text{(4)  Mg(s)  +  1/2 }}{{\text{O}}_{\text{2}}}{\text{(g)}} \to {\text{MgO(s)}}

This equation can be obtained by combining equations (1), (2), and (3):

Cannot create image: {\text{(1)  MgO(s)  +  2 HCl(aq)}} \to {\text{MgC}}{{\text{l}}_{\text{2}}}{\text{(aq)  +  }}{{\text{H}}_{\text{2}}}{\text{O(1)}} Cannot create image: {\text{(2)  Mg(s)  +  2 HCl(aq)}} \to {\text{MgC}}{{\text{l}}_{\text{2}}}{\text{(aq)  +  }}{{\text{H}}_{\text{2}}}{\text{(g)}} Cannot create image: {\text{(3)  }}{{\text{H}}_{\text{2}}}{\text{(g)  +  1/2 }}{{\text{O}}_{\text{2}}}{\text{(g)}} \to {{\text{H}}_{\text{2}}}{\text{O(1)}}

The pre-lab portion of this experiment requires you to combine equations (1), (2), and (3) to obtain equation (4) before you do the experiment. Heats of reaction for equations (1) and (2) will be determined in this experiment. As you may already know, ΔH for reaction (3) is –285.8 kJ.


In this experiment, you will

  • Combine three chemical equations to obtain a fourth.
  • Use prior knowledge about the additivity of reaction heats.
  • Determine the heat of combustion of magnesium ribbon.

Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

Option 1

Option 2

Additional Requirements

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

Standards Correlations

See all standards correlations for Chemistry with Vernier »

Chemistry with Vernier

See other experiments from the lab book.

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

Experiment 19 from Chemistry with Vernier Lab Book

<em>Chemistry with Vernier</em> book cover

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Dev Reference: VST0088

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