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What is the meaning of Charles Law?
Charles Law concludes that the volume of a given gas mass is directly proportional to its temperature (in Kelvin at constant pressure). Let us assume that the volume of the gas is denoted by V and the temperature of the gas is denoted by T at constant Pressure P. In Charles Law, volume changes according to the temperature in both positive and negative manner at constant pressure that the gas exerts.
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When comparing a material under two distinct situations, we may write the following from the previous statement:
V2/V1= T2/T1.
Or,
V1.T2=V2.T1.
This Charles Law equation shows that when the gas’s absolute temperature rises, the volume of the gas rises in proportion.
In another way, Charles Law is a variant of the ideal gas law. The law applies to ideal gases kept at constant pressure with varying temperatures and volumes.
The Formula for Charles Law
The formula for stating Charles Law is as follows:
VI /TI=VF /TF.
Where VI denotes the initial volume.
VF stands for the final volume.
TI denotes the initial absolute temperature.
TF stands for final absolute temperature.
It is important to understand that these are absolute temperatures measured in Kelvin, not in degrees Fahrenheit or Celsius.
Derivation of Charles Law
According to Charles Law, we know that the volume of a certain amount of dry gas is precisely proportional to absolute temperature at constant pressure. The following is a representation of the statement.
V∝T.
We can use the constant k to equal V and T because they are both directly changing.
V/T = constant = k.
In this case, the value of k is determined by the gas’s pressure, volume, and unit of measurement.
V*T=k——-(1)
Consider V1 and T1 as the starting volume and temperature of an ideal gas, respectively.
Charles Law equation (1) can therefore be written as
V1/T1=k——-(2)
After that, we will alter the gas’s temperature to T2. Alternatively, if the volume switches to V2, we write.
V2/T2=k——–(3)
Equating the two equations above (equations 2 and 3) yields
V1/T1=V2/T2.
Or,
V1T2=V2T1.
You are aware that heating a fixed amount of gas, that is, raising the temperature, also increases the volume. Similarly, as the temperature is reduced, the gas volume reduces. For every unit degree increase in temperature, the volume increases by 1/273 of its initial volume at 0 degrees centigrade.
For situations using Charles Law, it is critical to remember that the temperature unit must be in Kelvin, not Celsius or Fahrenheit, as previously stated. The absolute temperature scale is also known as the Kelvin temperature scale. To convert a temperature from Celsius to Kelvin, multiply the temperature by 273 per the Celsius scale.
According to Charles Law, gas volume (V) is precisely proportional to its temperature (T), which must be in Kelvin.
A change in temperature of one Kelvin unit equals a change in temperature of one Celsius degree. Remember that 0 degrees Kelvin equals -273 degrees Celsius, or “Absolute Zero”.
When the gas has the same mass and pressure, its density is inversely proportional to its temperature in Kelvin.
Real-life Applications of Charles Law
Some examples of the application of Charles Law in real life
- A scientist named Jacques Charles explained that the volume of gases increases and decreases with temperature rise and decrease, respectively. He utilised his discovered law to make a sight-seeing (hot-air) balloon, a famous application of Charles Law in real life.
- We apply the Charles Law ordinarily in real life. Let us start with an elementary example, a soda can. When you open a chilled can, you merely see bubbles. However, bubbles spill out the drink if you open a warm can. Why is this so? This is because of Charles Law. The volume of gas increases in case of a warmer can, and as the can opens, gas molecules find their way to bubble out more intensely.
- Another example of Charles Law application in real life is baking bread and delicious cakes. For manufacturing bakery products, yeast is used for fermentation, which produces carbon dioxide. When we bake any bread or cake, carbon dioxide expands because of the increase in temperature, and that is why bread and cakes have a fluffy appearance and texture.
- Charles Law also influences the human body as in the late spring season, i.e., summer season; our lungs load up with an enormous volume of air contrasted with the air volume present in the winters. Therefore, we can efficiently perform physical activities in warm weather.
Charles Law Application in Real Life
According to Charles Law notes, when the graph between volume and temperature at the constant pressure is plotted, it always gives a straight line known as isobar or isoplestics.
The application of Charles Law also states that when mass and pressure increase, the density of the gas is inversely proportional to its absolute temperature.
Air balloons in sports and meteorological observations are some applications of Charles Law in real life.
Conclusion
Charles Law also governs the operation of the Pop-Up Turkey Timer (thermometer). Let us look at how! To recall, Charles Law says that gases expand when heated. The Pop-Up Turkey Timer works on the same concept. The thermometer (or timer) is inserted inside the turkey. The gas inside the thermometer expands as the turkey temperature rises, so it is time to remove the turkey from the oven.
