Showing posts with label Expansion of Liquids. Show all posts
Showing posts with label Expansion of Liquids. Show all posts

Expansion of Liquids Problems with Solutions

We are solving series of problems basing on the concept expansion of liquids. The molecular force of attraction among liquid is comparatively less than that of solids. When heat energy is given to a solid, the recovery of molecules back to their original position is less probable than solids and hence expansion of liquids is more than that of solids. There is no specific length and area of cross section for a liquid and hence there is no linear and areal expansion. Expansion of liquids is studies only in terms of volume expansion. Liquid has to be taken in a container and the container will first absorb heat energy and it expands first. So the expansion of liquid appears to be different from real expansion and hence we need to study liquid expansion in terms of apparent and real expansions and to measure them we have different expansion coefficients.

Problem

A liquid is heated in a vessel and the relation between apparent and real expansion coefficients is given to us as shown in the diagram below. We need to find the coefficient of linear expansion of the solid container.


Solution

We know that the liquid has two different types of coefficients called real expansion coefficient and apparent expansion coefficient. When the container expands with the rise in temperature, real expansion coefficient is more than that of apparent expansion coefficient. We also know that the coefficient of real expansion is the sum of coefficient of apparent expansion and the volume expansion coefficient of solid container. Substituting the given data of the problem, it can be solved as shown in the diagram below.


Problem

Coefficient of real expansion of the liquid are given to us in the problem and coefficient of linear expansion of the material is also given to us in the data. We need to find the coefficient of apparent expansion of the liquid and the problem is as shown in the diagram below.


Solution

We know the relation between the apparent and real expansion coefficients and we can use it to solve the problem as done in the previous problem. Solution is as shown in the diagram below.


Problem

Coefficients of apparent expansion of a liquid in two different vessels is given to us and we need to find the difference between the coefficients of linear expansion coefficients and the problem is as shown in the diagram below.


Solution

As the liquid is same in both the cases, its coefficient of real expansion is same and it can be equated in both the cases basing on the definition.Solution is as shown in the diagram below.


Problem

There is certain mass of the liquid at a given temperature and there is some overflow of liquid when there is raise in the temperature. We need to find the coefficient of apparent expansion of the liquid and the problem is as shown in the diagram below.


Solution

We can express coefficient of apparent expansion of the liquid as the ratio of mass of the liquid over flown due to raise of the temperature to the remaining mass of the liquid after over flown. Taking that into consideration, we can solve the problem as shown in the diagram below.


Problem

A specific gravity bottle has certain mass of liquid in it at certain temperature and when the temperature is raised to a certain value, we need to know the mass of the liquid expelled and the problem is as shown in the diagram below.


Solution

We can solve the problem based on the definition of coefficient of apparent expansion of the liquid. We know that it can be the ratio of mass of the liquid expelled to the mass remaining after the raise of the temperature. Solution is as shown in the diagram below.


Problem

There is some mercury in a glass vessel of one liter volume and its volume remains constant in the vessel at all temperature and we need to find the volume of the mercury filled so that its volume appears constant at all temperatures. Problem is as shown in the diagram below.


Solution

For the level to remain constant at all temperatures, the expansion of mercury shall be similar to expansion of glass vessel. Taking that definition into consideration, we can solve the problem as shown in the diagram below.


Problem

A body is floating in the water with 98 % immersed at 4 degree centigrade. We need to know at what temperature the body completely gets immersed in the liquid and the problem is as shown in the diagram below.


Solution

We can use the definition of coefficient of apparent expansion as shown in the diagram below and solve the problem.


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Temperature and its Measurement 

Thermal Properties of Heat Complete Lesson

Heat is a disordered form of energy and to know the direction of flow of the heat, we need the concept of temperature. Temperature is a measure of the heat energy. Heat is measured with a unit called calorie and temperature is measured with kelvin in the standard international system. The rise in the temperature of a body causes the expansion in general in the body and it is called thermal expansion. To study this expansions, we need coefficients of expansions and they were separately defined for solid state, liquid state and gaseous state materials. 

Heat flows from one place to other in different ways called conduction, convection and radiation. Conduction need a solid medium, convection need a fluid media and radiation is not in need of any media for the propagation.

Here in this lesson we have discussed about all this topics in detail.

Expansion of Solids and Applications
                                                     

Anomalous expansion of water 

Expansion of Liquids Problems with Solutions


Heat and Thermodynamics Complete

Heat is a form of energy. Heat can be converted to other forms of energy’s and other forms of energy’s can also be converted into heat. Heat can be measured with a physical quantity called temperature. When heat energy is given to your body it expands. The expansion has to be studied separately for solids, liquids and gases.

The conversion of the heat energy into other forms and its applications are studied in the chapters called calorimetry and thermodynamics. The reason behind the temperature is nothing but the internal collisions of molecules of a gas and it is studied in the kinetic theory of gases.

This post is a collection of all the topics that are relevant to the heat and Thermo dynamics.

Posts available in the blog are 


Anomalous expansion of water

Anomalous expansion of water

Water has a peculiar property. When temperature is rises between 0 to 4°C water is not going to expand but it is going to contract. This special property is called anomalous expansion of water. It is because of the molecular configuration of the water.

When the temperature is decreased from 4°C to 0 degrees centigrade water does not contracts but expands.

Therefore at 4°C volume of the water is minimum and the corresponding density is maximum. This density is generally taken like a reference density of the water.

It is obvious that at 4°C density of the water is going to be maximum as the volume is minimum.

This property has a great importance in explaining the aquatic life existence during the winter season in the cold countries.

During the winter season due to the cold breezes the upper layers of the river will   get a lower temperature first. As a result the water becomes denser and it reaches to the lower levels. Because of the anomalous expansion property of the water, at the lowest part there will be temperature of 4°C. On the top of it and there will be water at 3°C and so on. Hence though the uppermost layer of the water is at 0°C, at the lower portions there will be higher temperatures and water can exist without freezing.

This helps for the survival of the aquatic life under the water.



Variation of density with temperature

Whenever the temperature of a liquid is increased, its volume increases and hence density decreases. Anyway mass of the liquid is going to be independent of temperature and it is always going to remain constant. Basing on this concept we can derive the relation between a densities are different temperatures as shown below.



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Expansion of Liquids

Whenever heat energy is given liquids are also going to expand like solids. The force of attraction between the liquid molecules is bit less when compared with the solids and hence expansion is going to be more in the case of the liquids. Solids have a specific shape and hence they have linear expansion, areal expansion and volume expansion. Liquids don’t possess any particular shape and they acquire the shape with respect to the container. As a result liquids have no linear and areal expansions and we can study the expansion of the liquid is only through volume expansion.

Solids have an advantage that we can supply the heat energy directly to them. But liquids have to be taken in a container and then heat energy has to be supplied to the container. First the heat energy is absorbed by the container and it expands. After receiving sufficient energy it will further pass it to the liquids and the liquid starts expanding.

At the initial stage when the solid is expanding it appears like the liquid level is falling down. It is because of volume expansion of the solid container. Therefore liquids have two types of expansion coefficients. One is the apparent expansion coefficient and the other one is the real expansion coefficient. Apparent expansion coefficient of a liquid depends not only on the nature of the liquid but also on the nature of the container.

Real expansion coefficient of the liquid depends only on the nature of the liquid but never on the container of the liquid.

Relation between coefficients of apparent expansion and real expansion

1.Consider a liquid in a long necked vessel as shown below. Let the liquid is filled up to a level A in the solid container.

2.When heat energy is supplied as the container expands the liquid level falls below the given level to B. A human eye cannot identify it because its value is small.

3.When the heat energy is further supplied the liquid level rises from the lower level B.

4.Though it appears like liquids is raising from A, it is actually raising from B. The expansion appears for as from A to C and it is called apparent expansion.

5.Expansion of liquid really happens from B to C and it is called real expansion.

6.The real expansion of the liquid is equal to the sum of apparent expansion of the liquid and the volume expansion of the solid container.



Coefficient of apparent expansion of the liquid is defined as the ratio of apparent change in the volume of the liquid to its original volume per 1°C rise in temperature.

Coefficient of real expansion of the liquid is defined as the ratio of real change in the volume to its original volume per 1°C rise in temperature.




Problem: 

A liquid is taken into different containers having different coefficients of linear expansions. The apparent expansion coefficient in one of the container is given then what is the apparent coefficient of expansion when the liquid is in the second container?

The concept behind the problem means coefficient of real expansion of a liquid depends only on the nature of the liquid .As the liquid is same, even though the containers are different it is going to have the same coefficient of real expansion. Basing on this concept the problem is solved in the above-mentioned diagram.


Problem and solution

A glass vessel of 1 liter volume how much of the mercury has to be filled so that the level of the mercury remains constant at all temperatures? Assume that volume expansion coefficient of mercury is a seven times the volume expansion coefficient of glass.

In solving the problem we have to apply a simple concept. If the level of the mercury has to remain constant at all temperatures, increase in the volume of the mercury shall be equal to the increase in the volume of the glass vessel.



To measure the apparent expansion coefficient of a liquid we have a small formula. It is the ratio of mass of the liquid expelled to the mass remaining per unit rise in temperature.

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