Determining the enthalpy of neutralization by calorimetry
Anam Iqbal
Partner’s name: Danielle Hodgson
TA’s name: Karinna
Section # 003
Due date: November 24, 2009
Introduction
The purpose of the experiment is to determine the enthalpy of neutralization reactions by calorimetry. Calorimetry, is the science of measuring the amount of heat. All calorimetric techniques are therefore based on the measurement of heat that may be generated (exothermic process) or consumed (endothermic process). The device used for measuring the heat changes in this experiment is called calorimeter. A calorimeter is a Styrofoam cup is used as a calorimeter, because it is a container with good insulated walls to prevent heat exchange with the environment.
A
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Of NaOH | Initial temp. Of HCL | Trial 1 | 24.5 | 24.0 | Trial 2 | 24.0 | 24.1 |
Table # 2: initial temperatures for neutralization of NaOH with HNO3 | NaOH | HNO3 | Trial 1 | 24.0 | 24.3 | Trial 2 | 24.1 | 24.0 |
Table #3: initial temperatures for neutralization of NaOH with Phenol | NaOH | Phenol | Trial 1 | 23.5 | 23.5 | Trial 2 | 23.9 | 23.9 |
Table #4: initial temperatures for neutralization of NaOH with unknown HCL | NaOH | Unknown HCL | Trial 1 | 23.9 | 23.8 | Trial 2 | 23.7 | 22.8 |
Table #5: concentrations | HCL | NaOH | HNO# | Phenol | concentration | 1.9027 M | 2.3955M | 1.749M | 0.5000M |
Results and calculations
Part A: neutralization of NaOH with HCL
Table #1: temperature changes every 2 sec till max. | 2 sec | 4 sec | 6 sec | 8 sec | 10 sec | 12 sec | 14 sec | 16 sec | Trial 1 | 34.0 | 35.0 | 35.3 | 30.0 | 33.0 | | | | Trial 2 | 30.0 | 31.0 | 32.0 | 33.0 | 34.0 | | | |
Table #2: temperature changes for every 10 seconds for 1 min. | 0 sec | 10 sec | 20 sec | 30 sec | 40 sec | 50 sec | 60 sec | Trial 1 |
The dependent variable in the experiment was the temperature and energy absorbed by the water.
always exchanges energy with the surroundings. Energy exchange can occur as work or as heat
In order to measure the heats of reactions, add the reactants into the calorimeter and measure the difference between the initial and final temperature. The temperature difference helps us calculate the heat released or absorbed by the reaction. The equation for calorimetry is q=mc(ΔT). ΔT is the temperature change, m is the mass, c is the specific heat capacity of the solution, and q is the heat transfer. Given that the experiment is operated under constant pressure in the lab, the temperature change is due to the enthalpy of the reaction, therefore the heat of the reaction can be calculated.
The first part of this lab’s objective was to find the calorimeter constant using DI water. We accomplished this by first checking the temperature and then adding 20 mL of cold DI water into our calorimeter. Next we collected 20 more mL of DI water in a 50 mL beaker and placed it onto a burner in order to heat it. We removed the beaker once the temperature of the water reached 60º celsius. After we removed the water, we poured it into the calorimeter with the cold water and took the temperature. The temperature ended up being 37º celsius. From this information we were able to calculate for qhot, qcold, qcal and Ccal. To be as accurate as possible we conducted this same test three more times and used the averages from all Ccal calculations as the final Ccal.
Experiment 2 focused on finding the enthalpy of solution of magnesium chloride. Testing the enthalpy of solution started with measuring out 10 mL of deionized water in a graduated cylinder for three separate trials, each trial having a different mass of magnesium chloride. The water was then poured into a well of a Styrofoam calorimeter then the initial temperature of water was taken using a temperature probe and the LoggerPro programming. A measured amount of magnesium chloride was placed in the same well as the water in the calorimeter,
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Direct calorimetry measures heat production. The indirect calorimetry examines the amount of oxygen and the carbon dioxide that is used. To assess the oxygen and carbon dioxide used, it is generated through the metabolic velocity.
Bomb calorimeter & The Usages Introduction: Like other calorimeters, the bomb calorimeter is used to measure the amount of heat that is released by an exothermic reaction. The term ‘bomb’ refers to its usage of a sealed container that contains an even smaller container within that can endure high pressures. Inside the smaller container which is surrounded by water, the reaction takes place. The main difference between a bomb calorimeter and all the other types of calorimeter is that the change in enthalpy (ΔH) isn't being measured.
We will be using 6 different fuels to heat up 100ml of water, and find out the changes of the temperature. We will measure the temperatures of the water before and after the experiment. We will burn heat the water for exactly 2 minutes, and check the changes in temperature. The change in temperature will allow us to work out the energy given off the fuel by using this formula:
This experiment was performed to determine the heat of neutralization between Hydrogen chloride (HCl) and Sodium hydroxide (NaOH). A temperature probe was used to measure the temperature of the reaction when the base (NaOH) was poured into the acid (HCl). The data was collected on logged on LoggerPro.
Introduction: The theory behind this experiment is the heat of a reaction (∆E) plus the work (W) done by a reaction is equal to
Purpose: To measure the heats of reaction for three related exothermic reactions and to verify Hess’s Law of Heat Summation.
ENTHALPY AND ENTROPY OF ZINC WITH COPPER SULFATE The CCLI Initiative Computers in Chemistry Laboratory Instruction
And copper (II) ions were reduced to copper because it gained electrons and its oxidation number changed from +2 in copper (II) ions to 0 in copper.
Introduction: Every chemical change is accompanied by a change in energy usually in the form of heat. If heat is evolved, the reaction is exothermic, and if heat is absorbed, the reaction is endothermic. The energy change of a reaction that occurs at constant pressure is called the heat of reaction or the enthalpy of reaction (ΔHr). This quantity of heat is measured experimentally by allowing the reaction to occur in a calorimeter. In this experiment you will determine the heat of neutralization when an acid and a base react to form 1 mole of water. In a perfect calorimeter, heat is exchanged only between the reaction and the calorimeters water. Technically, some heat may may be absorbed the calorimeter. All calorimeters exchange some heat with its environment. This amount of heat is called the calorimeters heat capacity (the amount of of heat required to raise its temperature 1∘Celsius). We are going to “pretend” that our calorimeter is the perfect calorimeter.