Category: Physics

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.

Introduction

The matter may be found on Earth in three different states: solid, liquid, or gaseous. Every matter is composed of incredibly tiny building components called atoms and molecules. These particles in a solid are strongly attracted to each other and vibrate in place without passing by each other. Despite not being as strong as it is in a solid, there is still an attraction between the particles in a liquid. The proximity and frequent movement of the particles in a liquid allow them to slip past one another. There is only a weak attraction between gaseous particles. They are continually moving and spread out compared to the particles in a solid or liquid. Here the particles do not interact when they collide; they just strike and bounce off of one another. This article provides a thorough understanding of the concept of matter of space between particles and attraction between the matter particles with specific instances.

Particles have Space between Them

Let’s observe a small activity to determine whether the particles are separated from one another; this is explained below.

Experiment

Take a beaker filled with 100 ml of water and then add 20 gm of sodium chloride (table salt) into it. Make sure to swirl the water with a glass stirring rod until all the salt has completely dissolved. The salt will dissolve, and then we will get a solution.

Observations

It has been observed that even after 20 gm of salt has been dissolved in 100 ml of water, the level of the water doesn’t actually rise. This displays how free and interparticle space-containing water atoms are. This area is known as the interparticle or intermolecular space. In this interparticle area, the salt granules that were scattered have settled.

Particles of Matter are Constantly Moving at Random

Diffusion and Brownian motion demonstrate that particles are moving.

Diffusion

A material will mix and disperse with another substance through a process called diffusion while its particles are in motion. To homogenize the mixture, this process is repeated. For instance, the ink diffuses in the water as a result of the random movement of water and ink particles. Ink migrates from areas of higher concentration to regions of lower concentration at a pace that is inversely associated with the liquid diffusion rate of the ink. Diffusion occurs in liquids, solids, and gases, however, it occurs more rapidly in gases and less efficiently in solids.

Brownian Motion

Brownian suspended several pollen grains in water and then examined them under a microscope. He saw that the pollen grains were moving in a zigzag pattern. The movement is significantly more evident when the water is warmed. Water is made up of randomly migrating atoms. As a result, the moving atoms frequently strike the pollen grains, causing them to migrate. As an example of Brownian motion, the pollen grains are travelling in this manner.

Particles of Matter Attract Each Other

A force acting on the particles of matter holds them together. Some substances crumble into powder, while others form tiny crystals, and still, others are challenging to separate. The strength of the force of attraction varies from one type of substance to another, depending on that substance. This is done so that the force of attraction between the particles can keep the particles inside them. This interparticle force of attraction exists in all substances that cause the attraction of particles. Therefore, to break objects, we must defeat the force of attraction. A varying amount of strength is necessary depending on the chemical.

Examples show that breaking a chalk is easier than breaking a nail. This illustrates how 

various material particles have varied levels of attraction. The attraction between particles of the same material is referred to as “cohesion.”

Summary

The particles are separated by a certain amount of space, in which the gaseous form of matter has the largest inter-particle space among the three states of matter. Interestingly, the interparticle gaps that exist in various types of matter are what give rise to the three states of matter, and therefore the density of different states of matter increases from a gas to a solid state (for example water vapor to water and then ice). 

Frequently Asked Questions

1. Define Matter.

Ans: A component that is made up of several types of particles, takes up space, and has motion is referred to as “matter.”

2. What Constitutes Matter?

Ans: Matter is made up of atoms, which are made up of electrons, protons, and neutrons.

3. How to Develop the Model of Particles of Gas and Liquid?

Ans: By compressing a flexible plastic container with a balloon on top, we can imitate the gas particles. We can also try to squeeze a water-filled container as part of their modelling of liquid particles.

Introduction

One type of energy that is essential to our existence is light. We are unable to envision a world without light. Light improves the beauty of everything around us and allows us to see. In both science and art, light is a crucial element. One of the crucial scientific instruments that enable scientists to examine things all across the world is light.

Some scientific theories claim that it is made up of particles, while others assert that it is made up of waves. What is the medium of propagation if the light is a wave? How does light move? We shall find answers to some of these questions in this article.

How does Light Travel?

Light can pass through a medium and in a vacuum. However, there won’t be any particles in a vacuum that light can’t reflect off of. Therefore, light is invisible in a vacuum. Light can reflect in the air when it strikes dust or other particles, making light visible in the atmosphere. Light may be thought of as having waves. Different light waves have varied wavelengths, and different light has different colours based on the wavelength. For instance, the shortest wavelength of light has a violet colour, whereas the highest wavelength of visible light has a red colour. Light, being a wave, may exhibit wave characteristics like diffraction and interference.

The answer to the question of how light typically moves is that it moves straightforwardly. However, the truth is that light’s smaller diffraction effect is the reason it appears to move in a straight line. The spreading out and the illumination of an area where a shadow is anticipated is known as diffraction, which is the bending of waves around an object. The wavelength of light is on the order of nanometers. We cannot see impediments of this size with our unaided eyes because the wavelength is too narrow. As a result, we see that light moves in a straight path. Rectilinear propagation of light is another name for the way that light moves in a straight line.

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Experiment with the Straight Line Motion of Light

Normal light travels in a straight line because there isn’t enough diffraction to cause any noticeable effects. We demonstrate that light moves in a straight line using a basic experimental setup. In front of a candle on the tabletop, arrange three cardboard sheets back to back. Ensure that the candles and cardboard sheets are arranged in a straight line. On each cardboard sheet, poke a pinhole after lighting the candle. To allow for the visibility of the candle’s flame, the holes must be made at equal heights. Now, observe which line light travels in by looking through the holes. Along the slender line of holes, the thin flame will be visible. Now move one of the cardboard sheets to either side and observe the flame. Can you see the flame? The flame won’t be seen when you move the cardboard sheet. Reposition the cardboard sheet in its original location. The flame may now be seen. The experiment diagram is shown below. From this experiment, we may infer that light moves in a straight line.

Examples of Straight-Line Motion of Light

• When a lamp, torch, or another source of light emits light, it travels in a straight line.
• When sunlight enters a dusty environment through tiny holes, a straight-line trail of light is apparent.
• The object will become invisible when an opaque object is placed in front of it. The reason for this is that an opaque object prevents light from bending through its corners.

Summary

The light rays move in a straight line. The minimized diffraction effects of light facilitate the propagation of the light in a straight path. Examples, where the light rays travel in a straight line, are the light ray that comes from a train, a torch, and/or a lamp.

Frequently Asked Questions

1. What is Rectilinear Propagation of Light?

Ans: The motion of the light rays in a straight line is termed the rectilinear propagation of the light.

2. Explain why Light Travels in a Straight Line?

Ans: Diffraction is a wave characteristic of light. Only when the wavelength of the light wave is of the order of the dimension of the size of the particle it collides with, and the phenomena of diffraction take place. The wavelengths of light are on the order of nanometers. Typically, a nanometer-sized item is invisible to the human eye. Light’s diffraction impact is therefore too modest to be taken into account and travels in a straight-line path.

3. Why is Light Invisible in a Vacuum?

Ans: Light can travel through the vacuum, however, since there are no particles available in the vacuum, light cannot reflect in a vacuum and therefore light is invisible in a vacuum.

Introduction

Pressure can be defined as the force exerted perpendicularly per square unit of area of any object. It is represented by the formula,                                                                                                                        

                                                             P = F ⁄ A

where P is the pressure, F is the force exerted on the object, and A is the area of the object. Pressure is measured in pascal, and is classified into absolute, atmospheric, differential, and gauge pressure. A change in pressure has different effects on different states of matter.

Change in Pressure

Since the pressure exerted on an object is the amount of force applied per unit area of that object, a change in area or a change in the amount of exerted force can result in a change in pressure. For example, if the surface area decreases, the pressure increases simultaneously when the surface area decreases, the pressure decreases provided that the force applied remains constant. 

Effect of Pressure on the States of Matter

Pressure change can have different effects on different states of matter. By exerting pressure on the matter particles, we can draw them closer. Therefore, applying pressure can cause liquids to turn into solids, and when pressure is applied to a gas that is contained in a cylinder, the gas begins to compress and turn into a liquid. As pressure rises, the volume of the gas reduces, which causes the gas to change into a liquid and then finally a solid. The volume of a gas is inversely related to its pressure and directly relates to the number of molecules it contains.

Pressure has less of an impact on solids because they are non-compressible forms of matter. By applying pressure and lowering the temperature, liquids can be transformed into solids.

Effect of Pressure on Equilibrium

The equilibrium will adjust to minimize a change in the pressure of a gaseous reaction mixture. If the pressure is raised, the equilibrium will change to favour a fall in the pressure. The equilibrium will change if the pressure is reduced to favour an increase.

When a system’s volume is reduced, the pressure will rise (and the temperature is constant). A greater number of collisions occur with the container’s walls. There will be fewer collisions and hence less pressure if there are fewer gas molecules. The equilibrium will change in a way that reduces the number of gas molecules, which will likewise reduce the pressure. To forecast which way equilibrium will shift in response to a change in pressure, we must consider how many gas molecules are involved in the balanced reactions.

For example, the chemical reaction between nitrogen and hydrogen is shown below:

                                                           N2 (g) + 3H2 (g)→ 2NH3↑

The proportion in the equation that balances is 1:3:2. In other words, the 1N2 molecule combines with the 3H2 molecule to produce NH3 gas (from the balanced equation). Four molecules of reactant gas must therefore be present to produce two molecules of product gas.

• Pressure buildup will favour the reaction which results in fewer gas molecules. Because there are fewer product gas’ molecules, the forward reaction is more advantageous. Due to the rightward shift in equilibrium, the yield of NH3 will rise.
• The reaction that produces more gas molecules will be more favourable as pressure drops. If there are more reactant gas molecules present, the reverse reaction is more favourable. As a result of the equilibrium shifting to the left, the yield of NH3 will decline.

Some Facts

• Pressure is directly proportional to the temperature.
• In contrast to solids and liquids, gases are more easily subjected to pressure.
• Compared to gases, solids and liquids are less sensitive to pressure.
• When air pressure is raised, the boiling point of water rises.
• The equilibrium will adjust to minimize the change in pressure of the gaseous mixture.

Frequently Asked Questions

1. Does Changing the Size of the Container Affect the Pressure?

Ans: No change in concentration could change the pressure if the equilibrium reaction does not involve a change in the number of molecules in the gas phase. Therefore, altering the container’s size without also altering the pressure would have no impact on the reaction. The number of molecules stays constant and applies the same pressure whether the container size decreases or grows.

2. How can the Physical Condition of the Matter be Altered?

Ans: It is also possible to change the physical state of matter by adjusting the pressure that is applied. For example, by applying pressure and lowering the temperature, gases can liquefy. 

3. How does Pressure Affect the Boiling Point of a Liquid?

Ans: All liquids evaporate with an expansion. The expansion and delay of vaporization are the results of pressure on the surface. As a result, when pressure is applied, the boiling point rises.