The specific capacity of heat is defined as the amount of heat which is required for one gram of substance at 1⁰C. To understand how to determine the specific heat capacity of a given solid by the method of mixtures we need to read the full article.
Aim of the Experiment:
To determine the specific heat capacity of a given solid by method of mixtures.
The materials which are required
A solid which is in small pieces
The Weight box
The Two half-degree of thermometer
The Clamp stand
Determination of Specific Heat of a Solid
It is very important to note for us that in this experiment the better insulated our calorimeter is the more accurate our results will be. The loss of heat by conduction is the main cause of error in this experiment.
The theory behind this specific heat test is based on the conservation of energy. Heat is a form of energy and in this case, it will be transferred between the sample and water. It should now be clear how convenient this specific capacity of heat test is because the only reason to perform this experiment is to measure the change in temperature of the water which is indirect of the change in heat of the solid.
In a hypsometer, the solid is heated uniformly above room temperature up to a fixed temperature and then it is added to cold water in a calorimeter.
Loss of heat = heat gained by the calorimeter and water.
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Put two thermometers that are A and B in a beaker that are containing water and note their reading. Take one of them (say A) to be standard and find the correction to be applied to the other that is B.
Now we need to put thermometer B in a copper tube of a hypsometer containing the power of a given solid. We need to put sufficient water in the hypsometer and place it on a burner.
Weigh the calorimeter with a stirrer and lid over it by the physical balance. We need to record it.
Then fill about half of the calorimeter with water that too at about 5 to 8°C below room temperature. Now we need to weigh it again and record it.
Heat the hypsometer about 10 minutes till the temperature of the solid remains steady.
Next we need to note the temperature of water in the calorimeter. Transfer the solid from the hypsometer to the calorimeter quickly and then stir the contents and record the final temperature of the mixture.
Then in the end we need to remove the thermometer A from the calorimeter and weigh the calorimeter with its contents and lid.
The specific heat of given solid by method of mixture is…………cal g-1 °C-1
Sufficient solid power should be taken to cover the tip of the thermometer properly.
Sufficient water should be taken in the hypsometer.
The solid should be dropped quickly and gently.
The calorimeters generally should be polished from outside to avoid excessive radiation losses.
The temperature of cold water should not be below the dew point.
The Sources of Error:
There is some heat lost while transferring hot solid into a calorimeter.
There may be some heat lost in conduction, convection and radiation.
The bulbs which are on the thermometer may not be well inside the solid.
The specific heat of solid is already calculated earlier.
Heat Capacity of Solids
The heat capacity of a substance is related to how much energy it takes to raise the temperature of that substance by one unit. It depends upon how much of the substance is being considered in terms of the amount of energy standardized per unit of the substance. The standardized unit could be a unit of mass. The standardized unit that generally makes comparison between different substances easiest is a mole amount containing Avogadro's number which is 6.025×1023 of molecules or the atoms as single unit molecules.
The capacity of heat per unit substance (denoted by C) is the increase in internal energy of a substance U. Per unit increase in temperature is denoted by T:C = (∂U/∂T)
We need to note that the surface area of our sample is in relation to its mass. The more the mass of our sample, the more heat it will absorb and then give off, which means the result will be more accurate.