chemistry - matter in our surroundings

Question 1

What is matter?

Answer 1

Matter is anything that has space, occupies mass and takes up volume.

Question 2

How is matter classified?

Answer 2

Matter is classified based on its physical properties and chemical nature

Question 3

What is matter made up of?

Answer 3

matter is made up of tiny particles

Question 4

list the characteristics of particles of matter

Answer 4

1. Particles of matter have space in between them
2. Particles of matter are continuously moving
3. Particles of matter attract each other
4. Diffusion takes place in different substances depending on the type of the substance
   `

Question 5

‘particles of matter are continuously moving’ Explain

Answer 5

the particles of matter will be continuously at motion, which means that they possess kinetic energy. The rate at which the particles will be moving will depend on the temperature of the particles. If the temperature of the particles increase, the speed of the particles will increase

Question 6

What is diffusion

Answer 6

Diffusion is when the particles of matter mix on their own without any assistance.

Question 7

‘particles of matter attract one another’ Explain

Answer 7

the particles of matter have a force of attraction between them, it varies from one state of matter to another, or on the type of substance

Question 8

what are the 3 types of matter?

Answer 8

the solid, liquid and the gaseous state.

Question 9

what is the solid state

Answer 9

solid is a state of matter. It has a definite shape and has a definite volume. It also has a fixed mass

Question 10

What is the liquid state?

Answer 10

liquid is a state of matter where it does not have a fixed shape but has a fixed volume. It takes up the shape of the container that it is placed in. Liquid is considered fluid.

Question 11

what is the gaseous state?

Answer 11

the gaseous state has no definite shape but and no definite volume. The volume depends on the container it is in.

Question 12

describe the rates of diffusion for all the states of matter?

Answer 12

the diffusion rate in liquids is higher in solid.
This is because the liquid state does not have a fixed shape and does not have as much intermolecular attraction as the solid particles.
Hence the particles in the liquid state will move freely as compared to the solid state. Because of this, the rate of diffusion is higher in liquid

however, gas has a higher rate of diffusion than liquid. gas are more highly compressible than solid and liquid. due to the higher speed of particles in gas and more space being in-between them, hence diffusion can take place faster

Question 13

what does the melting point of a substance indicate

Answer 13

the melting point of a substance indicates the force if attraction between particles
it also indicates the temoreature at which the solid can turn into liquid

Question 13

what does the melting point of a substance indicate

Answer 13

the melting point of a substance indicates the force if attraction between particles

Question 14

what is fusion?

Answer 14

fusion is when a substance at the solid state is being converted into liquid state

Question 15

why does the temperature remain the same when a solid melts?

Answer 15

Even when we are adding more heat to the melting substance, the temperature of the substance will not change. This is because all the heat will be used to overcome the force of attraction between the particles in the substance

Question 16

what is latent heat of fusion

Answer 16

Latent heat of fusion is the amount of heat energy required to convert 1kg of solid into liquid at atmospheric pressure. For water, the latent heat of fusion is 334*10^3 J

Question 17

what is the latent heat of evaporation

Answer 17

latent heat of evaporation the amount of energy required to convert 1kg of liquid into gas. For water, the latent heat of evaporation is 2260*10^3 J

Question 18

define boiling point

Answer 18

when we heat a substance, the particles in it will start to move faster. As this process continues, a certain temperature is reached where the particles have enough energy to break free from the forces of attraction. This temperature at which the substance starts to boil is known as the boiling point.

Question 19

what phenomenon is boiling

Answer 19

boiling is a bulk phenomenon

Question 20

: what is sublimation

Answer 20

sublimation is the process where a substance at a solid state will turn into the gaseous state without going through the liquid state

Question 21

what is evaporation

Answer 21

in the liquid state, the particles at the surface of the substance will have higher kinetic energy than the rest of the substance. Because of this, they are able to break away from the force of attraction of other particles. This phenomenon is known as evaporation. The change of liquid to gas below the boiling point Is known as evaporation

Question 22

what are the factors that affect the rate of evaporation

Answer 22

1. Increased Surface area
2. increase in temperature
3. decrease in humidity
4. increase in wind speed

Question 23

how does increased surface area affect the rate of evaporation

Answer 23

evaporation is a surface phenomenon. For example, when the cloths are left out to dry, spreading them out will increase the surface area exposed to the surrounding. Because of this, the cloths will dry faster.

Question 24

how does increase in temperature affect the rate of evaporation

Answer 24

as the temperature increases, the kinetic energy in the particles will increase. The particles will be able to gain more kinetic energy and turn into the gaseous state faster.

Question 25

how does decrease in humidity increase the rate of evaporation?

Answer 25

humidity is the amount of water vapor in the air. the air around us cannot hold more than a certain amount of water vapour
if the amount of water vapour is already high, the rate of evaporation will decrease

Question 26

how does evaporation cause cooling?

Answer 26

when one pours acetone one his palm, the particles of acetone will gain heat and evaporate. during this process, the palm looses heat and hence, it causes cooling

Question 27

why should we wear cotton cloths during summer?

Answer 27

our body tends so sweat more during summer. cotton being a good absorber of water, will absorb our sweat and exposes it to the atmosphere, hence cooling can take place faster and our body can feel cooler

Question 28

why are water droplets present on the outer surface of a glass with ice water

Answer 28

the surface of the ice water is cold. When the water vapour in the surroundings come into contact with the cold surface, they loose heat and change their state from gas to liquid