Tag: Temperature

Introduction

Everything in the universe consists of tiny particles called molecules, which are classified based on the distance and the attractive force between their constituents. Different substances have distinct properties such as mass, temperature, density, volume, pressure, etc. 

The process of transfer of heat is achieved through three different processes in matter, namely, conduction, convection, and radiation. It is studied under thermodynamics, which deals with thermal energy and its relationship to heat, work, temperature, energy, entropy, and other physical properties of matter. 

Isotherms and adiabats

Thermodynamic system

A thermodynamic system is defined as a collection of matter confined within specific boundaries. Within the system, transformations can take place internally. At the same time, interaction with the outside world can occur through the boundaries, which can have a definite permeability. 

Based on the type of the boundary of the thermodynamic system, it can be classified into three categories: isolated system, closed system, and open system. 

• In an isolated system, no energy or matter is exchanged across its boundaries, and no work is performed. An example is items packed in a vacuum bag.
• A closed system allows for energy transformation, but matter cannot cross its boundaries, as seen in a cylinder closed by a valve. 
• And finally, an open system allows for the free exchange of energy and matter across its boundaries, such as a pool filled with water.

Thermodynamic processes

Thermodynamic processes involve an energy transfer between two systems or between systems and their surroundings, resulting in changes in volume, pressure, or temperature. Depending on the type of process, the process can change the energy of the system and perform some work on or by the system.

To classify thermodynamic processes, we look at how they are performed and what conditions they are performed in. 

• An isothermal process is one where the temperature of the system remains constant while energy is exchanged in or out.
• An isobaric process keeps the pressure constant.
• An isochoric process occurs when there is no change in the volume of the system.
• Finally, in an adiabatic process, no heat is exchanged by the systems. We’ll discuss adiabatic processes in detail here.

What is an adiabatic process?

An adiabatic process refers to a thermodynamic process in which, no heat energy is exchanged between the system and the surroundings. To be considered adiabatic, the system must satisfy two conditions.

1. It must be completely isolated. 
2. The process must occur over a short enough time frame, which makes it impossible for heat transfer to take place. 

Work done in adiabatic process

We start with a cylinder with walls made up of an insulating material. We assume that it has a frictionless piston attached to it also made up of an insulating material, effectively preventing heat from escaping. 

Reversible adiabatic process

An adiabatic process is considered reversible if the system can go back to its original state with no alterations. However, this can’t be achieved practically since a reversible adiabatic process does not really exist in nature. But theoretically, such a process is known as an isentropic process and one example of such a process is the adiabatic expansion of a real gas.

Irreversible adiabatic process

If the system cannot return to its original state after the process has occurred, the process is termed irreversible and is accompanied by a change in the entropy of the system. One example would be heat transfer.

Application of adiabatic process

Adiabatic processes occur in the following scenarios:

1. The principle is used in refrigerators.
2. Some processes in a thermal engine are adiabatic in nature. 
3. Compressors and turbines also work on adiabatic principles. 
4. Igloos and thermos flasks are isolated systems and they utilise adiabatic principles.
5. Quantum harmonic oscillators work adiabatically.

Carnot cycle

Summary

This tutorial covered the topic of thermodynamic systems and processes, including the work done in adiabatic processes. The discussion also included the differences between reversible and irreversible adiabatic processes and the various applications of adiabatic processes.

Frequently Asked Questions

1. Give some examples for all thermodynamic processes.

There are four types of thermodynamic processes: isothermal, adiabatic, isobaric, and isochoric. Some examples of these processes include boiling water, refrigeration, the Carnot engine, heat pumps, the freezing of water into ice, pressure cooking, and vertical atmospheric airflow.

2. Differentiate isothermal and adiabatic processes.

3. What is the specific heat capacity?

The specific heat capacity refers to the amount of energy that must be supplied to one mole of a substance to increase its temperature by one degree.

4. What do adiabatic compression and expansion do?

Adiabatic compression leads to an increase in system temperature and adiabatic expansion causes a decrease in temperature.

5. What is the first law of thermodynamics?

The first law relates the internal energy of the system with the heat exchange the work done. According to the first law, internal energy is the difference of the latter two quantities.

Also Read: Adiabatic Processes Derivation

Introduction

The whole universe is composed of two parts; system and surroundings. There occurs an exchange of heat between the system and the surroundings. Thermodynamics tells us about the exchange of heat, different forms of energy, and the transformation of energy into work. It also explains some other properties of the system like temperature, pressure, density, enthalpy, entropy, etc.

Define Thermodynamics

Thermodynamics is a topic that derives the relationship between heat, energy, work, and temperature. According to thermodynamics, if the system does the work then its value will be negative and when work is done on the system its value will be positive.

Difference between Thermodynamics and Statistical Mechanics

Define System and Surroundings

System: The part of the universe in which all the matter remains is known as a system. 

Surroundings: The other part of the universe outside the system is known as the surroundings. The system and surroundings are divided by a boundary.

Classification of the system:

1. Open system: It has the capacity to exchange both energy and matter with the surroundings. In an open system, both the temperature T and pressure P are constant. For example, the human body.
2. Closed system: This system only exchanges energy with the surroundings. The entropy of a closed system is always constant. For example, water boils using a closed lid.
3. Isolated system: It exchanges neither matter nor energy with the surroundings. For example, a thermos flask is an example of an isolated system. 

Different types of processes in thermodynamics

• Isothermal process: In this process, the temperature (T) of the system is always constant.

1. Isochoric process: Here, the volume (V) of the system is always constant.
2. Isobaric process: In this process, the pressure (P) of the system remains constant.
3. Adiabatic process: In this process, the change in heat (Q) with the surroundings is zero.

Properties of thermodynamics

1. Intensive properties: These properties don’t change with the change in the amount of matter. For example boiling point, melting point, density, etc.
2. Extensive properties: These properties highly depend on the amount of matter in the system. For example mass, volume, etc.

Functions in thermodynamics

1. State functions: These functions change with the change in the state of a system. For example Enthalpy (H), internal energy (U), entropy(S), and density (d). 
2. Path functions: Heat (Q) and work (W) don’t depend on the state of a system, but rather depend on the path of a system. They are called path functions.

Define Enthalpy and Entropy

Enthalpy (H): It is a property of thermodynamics that indicates the overall heat capacity of a system. It is expressed by the sum of the system’s internal energy and the product of the pressure and volume of the system. 

H = U + PV

Depending on the symbol before the value of enthalpy, any reaction can be classified into two parts.

• Exothermic reaction: The reaction is called exothermic when heat is generated during a reaction. The value of enthalpy in an exothermic reaction is always negative.
• Endothermic reaction: When the system absorbs energy from the surroundings to execute a reaction is called an endothermic reaction.  The value of enthalpy in an exothermic reaction is always positive.

Entropy (S): It measures the extent of disorderness of a system. For a spontaneous reaction, entropy S is always negative and for a non-spontaneous reaction, entropy S is always positive.

Thermodynamic potential

Thermodynamic potentials are used to define a particular state of the system. They are internal energy (U), enthalpy (H), Gibbs free energy (G), and Helmholtz free energy (F).

Laws of thermodynamics

• Zeroth law: This law states: “if two bodies A and B are each in thermal equilibrium with some third body C, then they are also in equilibrium with each other.”
• First law: This law states:  “Energy can neither be destroyed nor be created, it can only be transferred from one form to another”. It is also called the “Law of conservation of energy.”

ΔQ = ΔU + W

ΔQ= Change in heat of a system.

ΔU = Change in internal energy of a system.

W = Work done

• Second law: This law states: “any spontaneously occurring process will always lead to an escalation in the entropy (S) of the universe.”

\[\Delta {S_{Total}} = {\rm{ }}\Delta {S_{system}} + {\rm{ }}\Delta {S_{surroundings}} > {\rm{ }}0\]

• Third law: This law states: “the entropy of a system approaches a constant value as the temperature approaches absolute zero.”

\[{S_{T = 0}} = 0\]

Daily life examples of thermodynamics

1. Human bodies sweat, producing heat from the body.
2. Melting of ice cubes.
3. Like A thermodynamic system, the human body exchanges mass and energy with the surroundings.

Summary

A type of heat energy that connects with other types of energy is called thermodynamics. Heat or work are two ways that energy is changed or exchanged. In thermodynamics, there are four processes. They are isothermal, adiabatic, isobaric, and isochoric. Thermodynamics explains many important properties of the system. Energy is the dominant focus of thermodynamics which is how it is used and transforms from one state to another. Thermodynamics frequently includes using heat to generate work like in the engines of automobiles and generating work to transfer heat like in the refrigerator.

Frequently Asked Questions 

1. Why does thermodynamics emphasize energy?

Ans: The first law of thermodynamics defines that the total energy of the system is always conserved. Neither energy can be created nor destroyed. It is only capable to change from one type to another. Like, in the combustion of fuel the chemical energy is transformed into thermal energy.

2. Why is it referred to as free energy?

Ans: Because it is readily accessible at all times, Gibb’s free energy is known as free energy. If necessary, the reaction can obtain this energy without exerting any effort.  Enthalpy (H) and also the product of the system’s temperature (T) and entropy(S) are added to determine the change in Gibbs free energy (G).

G = H +TS

3. What are the drawbacks of thermodynamics?

Ans: Thermodynamics can’t explain any properties of the system quantitatively. It doesn’t include the direction of the flow of heat. It can’t tell anything about the spontaneity of any reaction. These are the drawbacks of thermodynamics.

Introduction

Thermoplastics, polystyrene, and polyethylene can both be regularly moulded. It is therefore feasible to heat a foamed polystyrene cup while also moulding it into an irregular shape. For example, a dish. Individual molecules are separated from each other and move through one another in the polymeric material associated with thermoplastics. But even though the molecule may be straight or diverging, with molecular weights ranging from incredibly low to exceptionally high. Thermoplastic polyurethane (TPU) has a chemical formula \({C_{27}}{H_{36}}{O_{10}}\).

Define Thermoplastic Polymers 

1. Additional polymerization leads to the production of thermoplastics, which are softer and less brittle. Organic solvents can dissolve them.
2. Thermoplastics can also be heated to a soft state and then moulded into another structure while they remain warm.
3. They lose their ability to retain their carved shapes as they cool because they solidify. They can be warmed frequently and moulded into another form without altering their chemical components.
4. The thermoplastic polymer group is generally categorized as either amorphous or crystalline. The creation of thermoplastics involves combining subunits, which are small molecules.
5. A simple polymer chain can be produced using thousands of monomers. 
6. A simple polymer chain can be produced using thousands of monomers.
7. Though mild forces exist between sequences in polymers, the atoms are held together by powerful covalent bonds.

Features of Thermoplastic Polymers

1. They are polymers with very high molar mass.
2. With an increase in the temperature, intermolecular interaction in the cross-linking becomes weak. So a viscous liquid is produced.
3. There is the availability of thermoplastics which can be recycled easily.
4. They can behave as flame retardants.

Different types of Thermoplastics

1. Polystyrene: A polymer composed of repeating units, styrene is termed polystyrene. It is also known as poly-phenylethene. It’s actually a thermoplastic polymer, which indicates that when warmed, it weakens and melts and may be reprocessed. It resists substances like acids and bases and makes a great electrical insulator.
2. Polyvinyl chloride: PVC is properly known as Poly Vinyl Chloride. The polymerization of Vinyl Chloride creates PVC, a polymer. Several products, such as wires, raincoats, bottles, credit cards, etc. include PVC. It can be utilized to make a wide range of goods because it is fire and water-resistant.
3. Polypropylene: Polymerized propylene is used to create the synthetic polymer known as polypropylene. Polypropylene is moulded or produced into a wide variety of plastic goods wherein hardness, elasticity, lightweight, and temperature resistance are necessary.
4. Polyethylene: The most prevalent form of consumer plastic is polyethylene, which is also found in numerous everyday items. It’s a thermoplastic substance, which means that it can be repeatedly heated to a liquid state and then cooled to a solid state.

Influence of additives on the thermoplastics

1. Contrary to unprotected polypropylene, it has poor resistance to UV light. Additives like limited amines reduce the light and enhance the lifespan of the material.
2. Flame retardants, glass fibers, minerals, conductive fillers, colors, lubricants, and a range of many other polymer additives can be employed to enhance the mechanical and physical properties of polypropylene.

Application of Thermosets

1. Thermoplastic is an ingredient in producing sporting goods. Toys can also be made with it.
2. It is utilized in making the components of automobiles.
3. The thermoplastic polymer is employed to manufacture containers including shampoo bottles, drinking bottles, and food storage bins.

Advantages of Thermosets

1. It is a procedure that requires little energy.
2.  It gives a wide range of good quality products.
3. It produces very high-volume and precise manufacturing that is less expensive.
4. Metals can be substituted by a variety of substances with significant weight-saving benefits.

Disadvantages of Thermoplastics 

The following drawbacks of thermoplastics may influence the choice of material:

1. When exposed to UV rays or intense sunshine, thermoplastics deteriorate more quickly.
2. Not every thermoplastic is resistant to polar solvents, organic solvents, or hydrocarbons.
3. Some varieties exhibit creep when subjected to prolonged loading.
4. Under severe load, breakage occurs instead of deformation.

Types of polypropylene

The two primary forms of polypropylene are copolymers and homo polymers. Block copolymers, as well as random copolymers, are two more categories of copolymers. Different applications match every class more effectively than others.

Summary

Thermoplastics are simple to reuse because they solidify after cooling and exhibit no changes in chemical properties after being warmed and cooled numerous times. The repeating unit like urethane moiety is used to make thermoplastic polyurethane. This thermoplastic is usually produced through the interaction of a di-isocyanate and a polyol (organic compound). TPU has low TM between 87 to 90 °C and low Tg at 25 °C.

 

Frequently Asked Questions

1. Why can thermoplastics be recycled?

Ans: The intermolecular interactions in thermoplastic polymers are weak despite their strength. They have great recyclability.  Plastics can become less reusable as they go through the recycling process due to a variety of applications.

2. Why is PAI the strongest thermoplastic?

Ans: At 21,000 psi, PAI – Polyamide Imide (PAI) has the greatest tensile strength of almost any plastic. The maximum tensile strength of every unreinforced thermoplastic, radiation tolerance, intrinsic low combustibility, smoke production, and good thermal stability are all characteristics of this efficient plastic.

3. Do thermoplastics have an acidic nature?

Ans: Based on a variety of factors, any item may be technically or inherently hazardous or safe. TPU is harmless for many purposes and isn’t necessarily hazardous. It is employed in the biomedical field as well. A variety of factors may lead to polymers’ toxic effects.

Introduction

The human heart has four chambers that  are crucial to the circulatory system and the left and right ventricles are two of them. The blood is pumped throughout the body and to the lungs, where it is oxygenated, by the left and right ventricles working in tandem. The two ventricles cooperate to effectively remove wastes like carbon dioxide from the body and to keep the body’s blood oxygen-rich at all times.

Circulatory system

The circulatory system’s main job is to deliver blood, oxygen, and nutrition to the body’s cells and remove waste materials. The circulatory system is in charge of keeping the body’s internal environment, or homeostasis, stable.

Here’s how the circulatory system accomplishes its main functions:

1. Transporting oxygen: Blood pumped by the heart is rich in oxygen, which is essential for the cells of the body to function properly. The circulatory system carries oxygen to all parts of the body through the arteries and capillaries.
2. Transporting nutrients: The blood also carries nutrients, such as glucose and amino acids, to the cells of the body to provide energy and support growth and repair.
3. Removing waste products: The circulatory system removes waste products, including carbon dioxide and urea, from the body by transporting them to the kidneys, liver, and lungs for elimination.
4. Regulating temperature: It helps to regulate body temperature by transporting heat from the skin, which is the body’s main source of heat loss.
5. Supporting immune function: The circulatory system supports the immune system by transporting white blood cells to areas of the body where they are needed to fight infection.

Difference Between Left And Right Ventricle

Anatomy of the Left and Right Ventricle

The left ventricle is present at the lower left part of the heart and is the thickest chamber. It receives blood rich in oxygen from the left atrium and pumps it out by  the aortic valve, transporting it to the rest of the body. The right ventricle is present in the lower right part of the heart and is thinner compared to the left ventricle. The oxygen-deficient blood enters from the right atrium and pumps it out by the pulmonary valve to the lungs to pick up oxygen.

The left ventricle have much thicker because it has to pump blood to the rest of the body, thus requires more force. The left ventricle circular shape, compared to right ventricle, which is crescent-shaped.

Function 

The role of the left ventricle is pumping oxygen-rich blood to the rest of the body. This is done by contracting forcefully to create pressure that drives the blood out of the heart and into the aorta. The left ventricle also has a unique structure that allows it to maintain a high pressure for a longer period of time. This is because it has a thicker wall and a more efficient pumping mechanism than the right ventricle.

On the other hand, the right ventricle play a role in pumping oxygen-poor blood to the lungs. It does this by contracting and creating pressure that drives the blood out of the heart and into the pulmonary arteries, which carry the blood to the lungs. The right ventricle has a thinner wall than the left ventricle because it does not need to generate as much force to move blood to the lungs.

Conclusion

The circulatory system is made up of heart, arteries and blood. It delivers nutrients and oxygen to our body’s cells. Additionally, it eliminates waste materials like carbon dioxide. While the ventricle pumps blood out of the human heart, the auricles in mammals collect blood returning to the heart. Circulation is the continual flow of nutrients and waste materials through blood arteries. Maintaining heart health is crucial for our hearts to work properly.

 

Frequently Asked Questions 

1. What is double circulation?

Double circulation is a term used to describe the circulatory system of the human heart, in which blood flows twice through the heart before being supplied to the body. It involves two separate circulations of blood: pulmonary circulation and systemic circulation. Double circulation ensures that the oxygen-rich blood from the lungs is efficiently supplied to the body, while at the same time, the deoxygenated blood from the body is quickly returned to the lungs to be re-oxygenated.

2. Do humans have an open or closed circulatory system?

The human have a closed circulatory system. In this, the blood is separated from the tissues and organs by the walls of the blood vessels. 

3. What is a tricuspid valve?

Three unevenly shaped flaps make up the tricuspid valve. It is located between the right ventricle and right atrium, stops blood from flowing backward.

Introduction

The measurement of a system or substance’s heat is called its temperature. The pace of an enzyme-catalyzed reaction typically increases as the temperature rises in most chemical processes. Temperature is the internal energy contained within a particular system. Temperature can be measured by a thermometer. Temperature is measured in degrees Celsius, which is written as °C, and can be also measured in Kelvin (K) and Fahrenheit (°F). Temperature alters the states of matter by reducing or increasing the interatomic distances. 

Temperature Effect/Effect of Temperature

In several ways, the temperature has an impact on substances, processes, and enzymes. A substance’s state can be altered by varying its temperature. As the temperature rises, a solid can turn into a liquid, and as the temperature rises more, a liquid can turn into a gas. At high temperatures, a solid can be directly converted into a gas and this process is known as sublimation. Similar to the process where liquids may turn into solids at low temperatures, gases can become liquids by raising pressure while lowering the temperature. The rate of response of the transformation between the different states of matter is also positively or negatively impacted by temperature.

Learn More about Temperature and Heat. Check out more videos in 7th Class Science Lesson no 4.

The Effect of Change of Temperature on Solid State

As the temperature rises, the particles’ kinetic energy rises as well. As a result of the increase in kinetic energy, particles move faster and begin vibrating more quickly. The forces of attraction between the particles are weakened or eliminated by the heat energy. The particles start to travel more freely after leaving their fixed places. At some point, the solid melts and becomes a liquid. The melting point of a solid is the temperature at which it begins to dissolve into a liquid. When two distinct solid objects formed of the same substance are melted, they might combine to form a new one, a process known as fusion.

Effect of Change of Temperature on States of Matter

Heating and cooling are the two primary methods for converting states of matter. By applying heat, a solid can be transformed into a liquid. Similar to how a liquid may become a gas by heating. The opposite is also true; when a gas loses any of its thermal energy, it turns into a liquid. Further, removing a liquid causes its heat energy to solidify. The rising temperature causes a rise in the kinetic energy of the particles and the interspace between them. The force of attraction between particles is reduced by the increase in kinetic energy. 

Effect of Temperature on Pressure

A physical force that is applied to an item by anything in touch with it is called pressure. The pressure can be estimated by the force per unit area. Three variables which affect how much pressure a gas exerts on the walls of the chamber of a container in which it is contained and surrounded by a vacuum. These factors are the quantity of gas within the chamber, the chamber’s size, and the gas’s temperature. The link between the pressure and temperature of gases can be explained, according to the gas law, which states that the pressure of a given volume of a specific gas is precisely proportional to its temperature at a constant volume. This relationship between pressure and temperature is what is meant by the term “pressure-temperature relationship.” It can be modelled as:

  P∝T

A system’s temperature changes cause the molecules in the gas to move more quickly, increasing the pressure on the gas container’s wall. The system’s pressure rises as a result. The pressure likewise lowers when the system’s temperature rises. As a result, for constant volume, the pressure of a given gas is exactly proportional to the temperature.

The gas expands in volume at constant pressure as the temperature rises. The volume of the gas grows because it requires more space to move since the kinetic energy of the molecules increases as the temperature rises.

Effect of Temperature-Examples

The usage of light sticks or glow sticks is one illustration of how temperature affects the speed of chemical reactions. Chemiluminescence, a chemical process, occurs on the light stick. But neither is needed for nor produced by this reaction. The temperature has an impact on its pace. Precipitation reaction, activation energy, etc. are further examples.

Summary

The many states of matter are significantly impacted by temperature. The impact of temperature varies depending on the condition of matter. The kinetic energy of the state increases with temperature, yet the force of attraction varies depending on the state. The various states of matter are also impacted under constant pressure and volume. The pressure of the gas drops while the volume remains constant. The volume of the gas grows with constant pressure.

Frequently asked questions

1. What is the Liquid State of Matter?

Ans: Between the solid and gaseous forms of matter is the liquid state. Ice (solid), liquid as water, and gas as vapor are the three states of water. Although liquids do not have particular shapes, they do have specific volumes. The force of attraction in the liquid state is stronger than that in the gaseous state and weaker than that in the solid state. Atoms in this state have kinetic energies that are higher than those in solids, but lower than those in gases.

2. What Happens when the Temperature of a Gas Increases at Constant Pressure?

Ans. The temperature of a given system or gas container rises as the pressure in that system or container rises. While the pressure remains constant, the temperature rises, the velocity of the gas molecules increases, and the volume of the gas rise. As the gas’ temperature rises, the gas ascends into the atmosphere.

3. What is the Relationship between Pressure and Volume in Boyle’s Law?

Ans: When the temperature is maintained constant, Boyle’s Law states that the pressure exerted by a certain quantity of gas (the number of moles) is inversely proportional to the volume. The volume of the gas reduces with increasing pressure, and vice versa. The molecule tends to approach.