Chapter U5.8, Problem 3E

Interpretation Introduction

Interpretation: The possibility of measurement of heat energy of a combustion reaction by placing the thermometer directly into flames needs to be explained.

Concept introduction: Combustion is a chemical reaction in which a compound or an element undergoes reaction with oxygen and releases energy in the form of light and heat. A wide variety of substances undergoes combustion. Solid, such as wood and coal, liquids such as kerosene or methanol and gases, such as hydrogen and methane etc. all can combust.

Answer to Problem 3E

No, the heat energy of a combustion reaction cannot be measured by placing a thermometer directly into flames.

Explanation of Solution

Thermometer is an instrument used to measure temperature. Placing thermometer into flames measure the temperature of the combustion reaction but it cannot measure the heat given off by the reaction. Heat energy and temperature both are different in a reaction. So, placing thermometer directly into flames gives no measurement of heat energy of reaction.

Conclusion

Thermometer only measures the temperature of reaction.