A 2.20-g sample of phenol (C₆H₅OH) was burned in a bomb calorimeter whose total heat capacity is 11.90 kJ/°C. The temperature of the calorimeter plus contents increased from 21.50 to 27.50 °C. (a) Write a balanced chemical equation for the bomb calorimeter reaction.

Verified step by step guidance

1. Identify the reactants and products for the combustion of phenol. In a bomb calorimeter, phenol (C6H5OH) will react with oxygen (O2) to produce carbon dioxide (CO2) and water (H2O).
2. Write the unbalanced chemical equation for the reaction: C6H5OH + O2 → CO2 + H2O.
3. Balance the carbon atoms first. There are 6 carbon atoms in C6H5OH, so you will need 6 CO2 molecules on the product side: C6H5OH + O2 → 6 CO2 + H2O.
4. Next, balance the hydrogen atoms. There are 6 hydrogen atoms in C6H5OH, which means you will need 3 H2O molecules on the product side: C6H5OH + O2 → 6 CO2 + 3 H2O.
5. Finally, balance the oxygen atoms. There are 15 oxygen atoms on the product side (12 from CO2 and 3 from H2O) and 1 from C6H5OH, totaling 16 oxygen atoms. Therefore, you will need 7.5 O2 molecules on the reactant side to balance the equation: C6H5OH + 7.5 O2 → 6 CO2 + 3 H2O.

Key Concepts

Combustion Reaction

A combustion reaction is a chemical process in which a substance (usually a hydrocarbon) reacts with oxygen to produce carbon dioxide, water, and energy. In the case of phenol (C6H5OH), the balanced equation will show phenol reacting with oxygen to yield carbon dioxide and water, illustrating the release of energy in the form of heat.

Calorimetry

Calorimetry is the science of measuring the heat of chemical reactions or physical changes. In a bomb calorimeter, the heat released from the combustion of a sample is measured by the increase in temperature of the calorimeter's contents, allowing for the calculation of the energy produced during the reaction.

Heat Capacity

Heat capacity is the amount of heat required to change the temperature of a substance by one degree Celsius. In this context, the total heat capacity of the bomb calorimeter is crucial for determining the total heat released during the combustion of phenol, as it relates the temperature change to the energy produced.