4. Particle Model of Matter

Question 1

What is the Kinetic Theory?

Answer 1

The Kinetic Theory explains that all material in the Universe is made of very small particles.

It helps in understanding the properties of all materials, including living and non-living, in terms of the motion, separation, and interactions of these constituent particles.

Question 2

How is the specific heat capacity of a substance defined, and what is its relationship with energy, mass, and temperature change?

Answer 2

The specific heat capacity of a substance is defined as the amount of energy required to change the temperature of one kilogram of the substance by one degree Celsius.
𝐸 = 𝑚𝑐∆𝜃

Question 3

Define the specific latent heat of vaporisation. What is its relationship with energy and mass?

Answer 3

The specific latent heat of vaporisation of a substance is the amount of energy required to change the state of one kilogram of the substance from a liquid to a vapor with no change in temperature. specific latent heat of vaporisation = LV
equation:
𝐸 = 𝑚×𝐿𝑉

Question 4

Explain the concept of energy transfer by conduction and convection.

Answer 4

Conduction involves the transfer of energy through a substance by the collision of particles.

Convection involves the transfer of energy through the movement of particles within a fluid.

Question 5

How does the rate of energy transfer by heating depend on various factors?

Answer 5

The rate at which an object transfers energy by heating depends on its:
- surface area
- volume,
- the material from which the object is made
- the nature of the surface with which the object is in contact.

Question 6

Explain the expansion of substances when heated and provide examples of its hazards and usefulness.

Answer 6

Most substances expand when heated. This expansion can be hazardous, such as in the expansion of roofs and bridges, or useful, such as in the functioning of a bi-metallic strip thermostat.