May '13
7
MCAT Question of the Day | MCAT Course

• ### Q:

A student is performing bomb calorimetry for a combustion reaction. The bomb calorimeter normally holds 5 L of water with a heat capacity of 4.185 J/g•°C. However, the student misread the directions and used 6 L of ethanol which has a heat capacity of 2.423 J/g•°C. If the student calculates the energy released by the reaction assuming it was 5 L of water, what will be the difference between the actual energy of the reaction and the calculated energy? Note: the density of ethanol and water under normal conditions is 0.8 g/mL and 1.0 g/mL, respectively.

### A

The calculated energy will be higher than the actual energy because the total heat capacity of the calorimeter with ethanol is greater than with water.

### B

The calculated energy will be higher than the actual energy because the total heat capacity of the calorimeter with ethanol is less than with water.

### C

The calculated energy will be lower than the actual energy because the total heat capacity of the calorimeter with ethanol is greater than with water.

### D

The calculated energy will be lower than the actual energy because the total heat capacity of the calorimeter with ethanol is less than with water.

Tags: Thermochemistry | Quantitative Skills | Suggest a tag
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