Thermochemistry is a branch of chemistry that deals with the study of the heat produced or absorbed during chemical reactions and physical changes. It involves the measurement of the heat change that occurs during a chemical reaction or a physical process, and the use of this information to calculate the enthalpy change of the reaction or process.
In a thermochemistry lab, students are typically asked to conduct an experiment to determine the enthalpy change of a chemical reaction or a physical process. The experiment typically involves measuring the temperature change of a substance during a reaction or process, and using this information to calculate the enthalpy change.
There are several ways to measure the temperature change of a substance during a reaction or process. One common method is to use a calorimeter, which is a device that is designed to measure the heat exchange between a substance and its surroundings. Calorimeters come in various forms, such as coffee cup calorimeters and bomb calorimeters, and they are used to measure the heat of reactions or processes under constant-pressure or constant-volume conditions, respectively.
To conduct a thermochemistry lab experiment, students must first prepare a list of materials and equipment needed for the experiment, and then follow a set of procedures to ensure accurate and reliable results. The experiment typically involves the following steps:
Set up the calorimeter and prepare the substances to be used in the experiment.
Measure the initial temperature of the substances and record it.
Conduct the chemical reaction or physical process, and measure the temperature change that occurs.
Calculate the enthalpy change of the reaction or process using the measured temperature change and the known heat capacity of the calorimeter and the substances.
After completing the experiment, students should write a lab report to document their findings and to communicate the results of their work to others. A typical lab report should include the following sections:
Introduction: This section should provide an overview of the purpose of the experiment and the background information relevant to the study.
Materials and methods: This section should describe the materials and equipment used in the experiment, as well as the procedures followed.
Results: This section should present the data collected during the experiment, along with any necessary calculations.
Discussion: This section should interpret the results of the experiment and discuss their significance in relation to the research question or hypothesis being tested.
Conclusion: This section should summarize the main findings of the experiment and discuss their implications.
References: This section should list any sources cited in the report.
In conclusion, thermochemistry is an important branch of chemistry that enables us to understand the heat exchange that occurs during chemical reactions and physical processes. Conducting a thermochemistry lab experiment requires careful planning and execution, and the results of the experiment should be documented in a thorough and well-written lab report.
Make sure you label the data tables at the tops and sides. Materials and Devices: 2. Lab Report Format For the Lab Report, use steps 1 through 10 below. Tangent lines were drawn on the graph in order to determine the initial and final temperatures of the two liquids. But it is NOT required for this report STEP 10.
Results Description of what the data means. Then, we obtained solid NaOH and weighed about 2 grams to the nearest thousandth decimal point. If you can, begin your title using a keyword rather than an article like 'The' or 'A'. For the final experiment, the procedure is very similar to its predecessors. After a few seconds of data collection from the separate liquids, they were mixed together and stirred with the sensors until there was no time left.
A well known method of estimating missing temperature observations has been refined and applied to estimate monthly temperature with a higher accuracy. How about the enthalpy? For the first part, we will be finding the heat of neutralization for a strong acid strong base reaction using a HCl and NaOH solution. Many reactions are open to a constant atmospheric pressure. In order to achieve maximum accuracy, we must know exactly how much heat will be lost, so that the results of the next two experiments will be as correct as possible. We have to be patient with our timing during the performance of the experiment. Allow the temperature probe to sit in the water for a few minutes before recording the temperature.
Finally, we calculated the calorimeter constant using the formula listed in the Introduction section. Then, using the values given, determine the identity of the metal and then calculate the percent deviation of your calculated specific heat value from the accepted value. Figure 2: Similar to the previous graph, the temperature rose very quickly after 30 seconds and slowly started decreasing as time went on. If they are insulated from their surroundings, the amount of heat lost from the hotter substance equals that gained by the colder one. Pour the acid into a coffee cup and put the thermometer in another cup with a hole. The example below explains the steps calculating enthalpy change to transform graphite into diamonds.
In this case, draw a conclusion from each of the two sections. By measuring the change in temperature that occurs with the interaction of two different reactants, we were able to determine both the calorimeter constant and the change in enthalpy of a given reaction. Despite the difference, both are the only methods that energy can be transferred between the system and the surroundings. First, we measure as close as we can to 50 g of a base of our choice in a 100-mL graduated cylinder. Next, we obtain a polystyrene cup to use as our calorimeter and fill it with 100 g of water. Next, we obtain a polystyrene cup to use as our calorimeter and fill it with 100 g of water. EACH STEP IS A SEPARATE ITEM.
Make sure the metal is completely submerged in the boiling water and is not in contact with the sides of the beaker. You will be simulating this reaction in this part of the experiment. During this process the amount of heat released or absorbed is measure by changes in temperature. The method for determining it is like so: 98. The results were rather mixed, as some numbers more closely resembled the theoretical values than others did. Then the digital thermometer was used to measure the temperature.
Then, when time was up, we used Graphical Analysis to print the resulting temperature vs. The main concept is to observe the change in enthalpy that results from the various reactions between strong and weak acids and bases. Description of Procedure A. Despite this part, the experiment was an excellent opportunity to get more familiar with the lab instruments and a hands on the practice of the laws of thermochemistry. Sometimes it will rise, then fall, and rise again due to the uneven distribution of heat within the calorimeter. Background information and theory: Thermodynamics is the study of heat and its transformations and the branch of thermodynamics that deals with the heat involved in chemical and physical change is called thermochemistry.
Heat capacity is the quantity of heat of a system that is required to change its temperature by 1ºC while specific heat is amount of heat required to raise the temperature of 1 gram of a substance by 1 ºC. All ammonium nitrate solutions must be disposed of in the CHEM 2BH Exp. Recorded temperature for extended reaction time. After completing this lab, you will better understand the reasons behind these and other thermal phenomena. Temperature readings that were not precisely taken also may lead to error values. This experiment is vital to the success of the following two thermochemistry experiments.
The ideas and concepts involved in thermodynamics are in your everyday experiences. Begin data collection and record the temperature for at least two minutes. We have to be precise with the temperature we achieve at the beginning. It is recommended you label each picture added. Introduction: Thermochemistry is concerned with the heat absorbed or evolved in a chemical reaction.