Experimental determination of Specific Heat of Water Experiment number: When the current passes through the heating coil, the coil warms up and transfers heat to the water and the inner container of the calorimeter the outer container is insulated from the inner one by polystyrene; therefore we do not have to consider the heating of the outer container of the calorimeter.
Thermal Physics - Lesson 2 Calorimetry Calorimeters and Calorimetry Measuring the Quantity of Heat Calorimeters and Calorimetry Calorimetry is the science associated with determining the changes in energy of a system by measuring the heat exchanged with the surroundings.
Now that sounds very textbooky; but in this last part of Lesson 2, we are going to try to make some meaning of this definition of calorimetry. In physics class and for some, in chemistry classcalorimetry labs are frequently performed in order to determine the heat of reaction or the heat of fusion or the heat of dissolution or even the specific heat capacity of a metal.
These types of labs are rather popular because the equipment is relatively inexpensive and the measurements are usually straightforward.
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|When two or more objects at different temperatures are brought together in an isolated environment, they eventually reach the same temperature by the process of heat exchange. That is, warmer materials transfer heat to colder materials until their temperatures are the same.|
In such labs, a calorimeter is used. A calorimeter is a device used to measure the quantity of heat transferred to or from an object. Most students likely do not remember using such a fancy piece of equipment known as a calorimeter.
Fear not; the reason for the lack of memory is not a sign of early Alzheimer's. Rather, it is because the calorimeter used in high school science labs is more commonly referred to as a Styrofoam cup. It is a coffee cup calorimeter - usually filled with water.
The more sophisticated cases include a lid on the cup with an inserted thermometer and maybe even a stirrer. Coffee Cup Calorimetry So how can such simple equipment be used to measure the quantity of heat gained or lost by a system?
We have learned on the previous pagethat water will change its temperature when it gains or loses energy. So if the mass of water and the temperature change of the water in the coffee cup calorimeter can be measured, the quantity of energy gained or lost by the water can be calculated.
The assumption behind the science of calorimetry is that the energy gained or lost by the water is equal to the energy lost or gained by the object under study. So if an attempt is being made to determine the specific heat of fusion of ice using a coffee cup calorimeter, then the assumption is that the energy gained by the ice when melting is equal to the energy lost by the surrounding water.
It is assumed that there is a heat exchange between the iceand the water in the cup and that no other objects are involved in the heat exchanged. The value of a lid on the coffee cup is that it also reduces the amount of heat exchange between the water and the surrounding air.
The more that these other heat exchanges are reduced, the more true that the above mathematical equation will be. Any error analysis of a calorimetry experiment must take into consideration the flow of heat from system to calorimeter to other parts of the surroundings.
And any design of a calorimeter experiment must give attention to reducing the exchanges of heat between the calorimeter contents and the surroundings.
Bomb Calorimetry The coffee cup calorimeters used in high school science labs provides students with a worthwhile exercise in calorimetry. But at the professional level, a cheap Styrofoam cup and a thermometer isn't going to assist a commercial food manufacturer in determining the Calorie content of their products.
For situations in which exactness and accuracy is at stake, a more expensive calorimeter is needed. Chemists often use a device known as a bomb calorimeter to measure the heat exchanges associated with chemical reactions, especially combustion reactions. Having little to nothing to do with bombs of the military variety, a bomb calorimeter includes a reaction chamber where the reaction usually a combustion reaction takes place.
The reaction chamber is a strong vessel that can withstand the intense pressure of heated gases with exploding. The chamber is typically filled with mostly oxygen gas and the fuel.
An electrical circuit is wired into the chamber in order to electrically ignite the contents in order to perform a study of the heat released upon combustion. The reaction chamber is surrounded by a jacket of water with a thermometer inserted. The heat released from the chamber warms the water-filled jacket, allowing a scientist to determine the quantity of energy released by the reaction.
Wikimedia Common s; thanks to Lisdavid Solving Calorimetry Problems Now let's look at a few examples of how a coffee cup calorimeter can be used as a tool to answer some typical lab questions. The next three examples are all based on laboratory experiments involving calorimetry.
A physics class has been assigned the task of determining an experimental value for the heat of fusion of ice. Anna Litical and Noah Formula dry and mass out They place a lid on the coffee cup and insert a thermometer. After several minutes, the ice has completely melted and the water temperature has lowered to So if an attempt is being made to determine the specific heat of fusion of ice using a coffee cup calorimeter, then the assumption is that the energy gained by the ice when melting is equal to the energy lost by the surrounding water.
Experiment 4-Heat of Fusion and Melting Ice Experiment In this lab, the heat of fusion for water will be determined by monitoring the temperature changes while a known mass of ice melts in a cup of water.
The heat of fusion of a substance is the heat exchange required to melt one gram of the substance (calories/gm). In this part of the experiment, the heat of fusion of water will be determined.
Warm water will be used to melt ice, and the change in temperature of the water in the calorimeter will be used to compute the amount of energy extracted. Feb 07, · I'm taking a first year physics course and our upcoming lab is an experiment to determine the Heat of fusion for ice. There are a few questions that I have.
mA is the mass of the reservoir and stirrer (aluminum) c is the speci c heat of water cA is the speci c heat of the (aluminum) reservoir q is.
Feb 23, · What assumption did we make about heat lost by the water in the calorimeter as compared to heat gained by the melting ice? AND Extension: Design an experiment to find out if an ice cube taken from a freezer and immediately placed into a calorimeter needs the same amount of energy per gram for melting as does an ice Status: Resolved.
Could you give me Conclusion and do the Questions?. EXPERIMENT 3. THE LATENT HEAT OF FUSION OF ICE. A small amount of ice is placed in a calorimeter containing water%(2).