Calorimetry Lab Report

This lab report will most likely be used if your taking the class "Chemistry 1". It includes an abstract, data, results, calculations, discussion, conclusion, and post lab questions.

Experiment 25: Calorimetry

Abstract:

The goals of this experiment were to find the specific heat of a metal, determine the enthalpy of

neutralization for a strong acid-base reaction, and determine the enthalpy of a solution for the dissolution

of a salt. A calorimeter was the laboratory tool used to measure the quantity and direction of heat flow

with the chemical or physical change. The change in heat in a chemical reaction is quantitatively

expressed as the enthalpy of a reaction. Which can also be expressed as ΔH. Enthalpy is negative in

exothermic reactions, and positive in endothermic reactions. The change in heat in an acid-base solution,

the specific heat of a metal, and the change in heat in the dissolution of a salt water are the three

quantitative heat measurements for the experiment. Specific heat can be measured by the temperature

change of one gram of a substance; so that 1 o C. Energy (J) = specific heat (J/g o C) x mass (g) x ΔT ( o

C). In this experiment, we will assume that the specific heat of the substance will be constant over the

temperature change (ΔT) of the experiment.

In part B of this experiment, the reaction of a strong acid with a strong base determined the

enthalpy of neutralization in the solution. The two reactions that took place were H 3 O + (aq) + OH -

(aq) 2H 2 O (l) + heat, and HCl + NaOH H 2 O + NaCl. The equation used to find the change in

enthalpy was ΔH n = -specific heat H2O x combined mass acid + bass x. In part C of the experiment,

when a salt dissolved in water, energy was either absorbed or evolved; whether or not the magnitude of

the salt’s lattice energy and the hydration energy of its ions. The lattice energy, or an endothermic

quantity of a salt; and the hydration energy, or an exothermic quantity of its composite ion, account for

the amount of heat absorbed or evolved when one mole of the salt dissolves in water. The enthalpy of a

solution is calculated using the equation ΔH s = (-energy change H2O + -energy change salt )/mole salt.

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