Kinetic Particle Model of Matter- mistakes notes

Question 1

what are the two types of energies that affect the motion of particles in an object?

Answer 1

Kinetic and potential energy

Question 2

What causes the storage of energy in the form of elastic potential energy in the particles of an object?

Answer 2

A displacement of the particles from their mean position as determined by intramolecular forces

Question 3

If the temperature of an object increases, what must be happening to the average kinetic energy of its particles?

Answer 3

Since temperature is directly proportional to the average kinetic energy of particles in a substance, increasing temperature will result in an increase of the average kinetic energy of its particles

Question 4

What is internal energy?

Answer 4

The sum of kinetic energy of the particles in a system and the potential energy stored in a system

Question 5

What is temperature?

Answer 5

A measure of the average kinetic energy of the particles in a substance

Question 6

What is heat?

Answer 6

The transfer of thermal energy through a substance or between substances

Question 7

Determine the energy transformations that occur when the steam produced in a coal fired power plant causes the turbine to spin

Answer 7

Chemical energy stored in the coal is transferred to heat energy during combustion that is then transferred to kinetic and potential energy in the water as it turns to steam. The kinetic energy in the steam is transferred to kinetic energy in the rotating turbines

Question 8

Explain what happens to the potential energy of a bond if the bond is stretched or compressed away from its ideal length

Answer 8

The potential energy in a bond is at a minimum when its particles are at their mean separation, so an increase or decrease in length results in an increase of potential energy stored

Question 9

What is the difference between heat and temperature

Answer 9

Heat is a transfer of energy between objects whereas the temperature of a object is a measure of the average kinetic energy of particles in that object

Question 10

Identify the key features of the kinetic particle model

Answer 10

• all matter is made up of smaller particles in constant motion; they have kinetic energy
• collisions between particles are perfectly elastic, kinetic energy is conserved
• temperature of the particles is proportional to the average kinetic energy
• particles obey classical mechanics and only interact with one another when they collide

Question 11

convection

Answer 11

process by which energy is transferred through the bulk movement of fluid

Question 12

conduction

Answer 12

the process by which energy is transferred by the collision of atoms

Question 13

radiation

Answer 13

energy transferred across space, the process by which heat is transferred without the need for a medium, energy from radioactive atoms

Question 14

List in order of the electromagnetic spectrum from increasing to decreasing

Answer 14

x-ray, visible, infrared

Question 15

Explain why the temperature at the surface of a large body of water is generally warmer than the water lower down

Answer 15

The temperature at the surface of a large body of water is generally warmer than the water lower down as it is exposed to the radiation of the sun and conduction with the warmer and thereby increasing the average kinetic energy of the particles, compared to the water further down which is entirely dependent on the conduction of the heat from the upper sections

Question 16

describe the heat exchanges that occur in the process of energy being transmitted from the sun onto the surface of the Earth and eventually into the movement of air in the form of wind?

Answer 16

Heat is transferred from the sun in the form of radiation until it comes into contact with the particles in the atmosphere. Heat from these particles is transferred by either conduction or convection to other particles in the atmosphere until eventually heat is transferred from these particles to the surface of the earth by conduction

Question 17

Describe all the key features of the kinetic particle model

Answer 17

• all matter is made up of small particles in constant motion; they have kinetic energy
• all collisions between particles are perfectly elastic; kinetic energy is conserved
• the particles obey classical mechanics and only interact with one another when they collide
• The temperature of the particles is proportional to the kinetic energy of its particles

Question 18

Distinguish solids

Answer 18

solid: the particles oscillate around a mean position, but the kinetic energy of the particles is insufficient to overcome the bonding caused by intramolecular bonding

Question 19

Distinguish liquids

Answer 19

the kinetic energy of the particles is sufficient enough to allow them to move from their mean position and store energy in the form of potential energy. The distance between the particles increases and allows them to slide past one another

Question 20

distinguish gas

Answer 20

the kinetic energy of the particles is sufficient enough to allow them to break entirely free from their intramolecular bonds which allows the distance between particles to increase greatly

Question 21

Use the kinetic particle model and the concept of intramolecular bonding to explain how one object can be a better conductor of heat than another

Answer 21

Different objects have different intramolecular bond strengths that help keep the particle in place. In a substance with a weaker intramolecular bond strength, an addition of heat would allow the particles to move more freely and therefore collide with more particles which would separate the heat quickly. A more tightly bond material would impact the freedom of the particles, reducing the amount of collisions and therefore reducing the speed of transfer

Question 22

Explain how scientists can use the light emitted by a distant source to estimate its temperature

Answer 22

Different wavelengths of light emit different temperatures. Astronomers estimate the temperatures of distant objects by comparing the wavelengths of incoming light to those that would create them

Question 23

Why don’t we talk about the temperature of individual particles?

Answer 23

Even though the total kinetic energy of an object is a constant and fixed temperature and therefore, so is the average kinetic energy of the particles, individual particles are constantly colliding and the individual kinetic energy thus changing therefore there is no way to know the individual temperature of a particle.

Question 24

What would be the effect on the temperature of a substance if the collisions that were taking place between its particles were not perfectly elastic

Answer 24

If the collisions were not elastic, there would be a loss of kinetic energy during the collisions and therefore the total kinetic energy of the objects particles would decrease over time. This means that the temperature of the object would decrease over time.

Question 25

When a scientist wishes to cool a substance to very low temperatures, they often use a process called evaporative cooling which consists of the removal of the most energetic particles in the substance. Explain why this would result in cooling.

Answer 25

The most energetic particles are those that have a kinetic energy above the average kinetic energy of the particles within the substance undergoing cooling. By removing these particles the scientists are effectively reducing the average kinetic energy of the particles within an object and thus cooling it down.

Question 26

Describe brownian motion

Answer 26

The random motion of small objects suspended in fluid as a result of them being bombarded by the particles of the fluid

Question 27

Describe how the addition of heat can affect a substance

Answer 27

The addition of heat will cause an increase in the internal energy of the substance. This could be due to an increase in the total kinetic energy of the substance which would also cause an increase in the average kinetic energy of the particles in that substance and thus its temperature. Or it could be due to an increase in the potential energy stored in the intramolecular bonds of the substance

Question 28

What is heat conduction?

Answer 28

The process by which energy is transferred through the collision of atoms

Question 29

What is the process of heat convection

Answer 29

Heat convection occurs due to one area of fluid being warmer than the rest of the substance. The heat conduction occuring in this region causes the hotter, more energetic particles to move out into the areas containing the cooler, less energetic particles. In this way heat is transferred throughout the substance.