# Thermodynamics Lab Essay

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Thermodynamics- Enthalpy of Reaction and Hess’s Law
Objectives:
1. To calculate the heat of reaction of a given reaction using the concepts derived from Hess’s Law.
Pre-lab Questions:
1. Define Heat of Reaction.
The enthalpy change associated with the completion of a chemical reaction.
2. Define Specific Heat.
The energy it takes to raise the temperature of 1 gram of a substance by one degree Celsius.
3. Calculate the heat of reaction assuming no heat is lost to the calorimeter. Use correct significant figures.
Q = c x m x t q = (4.18)(1.02 g/ml x 50ml )(3.9 oC) = -831 J
4. In problem 3 above, the calorimeter has a heat capacity of 8.20 J/goC. If a correction is made to account for heat absorbed by the calorimeter,
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What is meant by calorimetry?
Calorimetry is the science of measuring the heat of chemical reactions or physical changes
2. How does graphical analysis improve the accuracy of the data?
By precisely graphing data points, one is able to improve the accuracy of the data due to being able to accurately calculate, not predict, the initial temperatures that the solutions had at time 0 by extending the graph backwards 20 seconds.
3. What is the meaning of the negative sign in front of the brackets in the heat of reaction equation?
The negative sign indicates that the given reaction is