Matter in Our Surroundings Science - Matter in Our Surroundings

Evaporation that occurs directly from the solid phase below the melting point is called as:

On increasing the temperature, the rate of evaporation _________?

Matter is made up of:

The presence of a significant number of charge carriers makes plasma as _____________?

Why does the boiling point of water decrease at higher altitudes?

What is the chemical name of dry ice? (Carbon dioxide (solid), Ice, Water vapor)

As the temperature rises, particles move ________. (Faster, Slower, Randomly)

At room temperature, the forces of attraction between the particles of solid substances are ________ than those which exist in the gaseous state. (Same, Stronger, Weaker)

Sublimation is the change of gaseous state directly to solid state without going through the ________ state. (Liquid, Gas, Vapour)

With an increase in temperature, the kinetic energy of the particles also ________. (Increases, Remains same, Decreases)

Red brown bromine vapour diffuse into air in a gas jar but the colourless air molecules do not diffuse into bromine vapour.

In pressure cooker water boils above 100°C.

Solid carbon dioxide is stored under low pressure.

Sea water boils below 100°C.

What is the physical state of water at:

1. 250ºC
2. 100ºC

Convert the following temperature to celsius scale:

1. 300K
2. 573K

Give reasons:
A wooden table should be called a solid.

The mass per unit volume of a substance is called density. (density = mass/volume). Arrange the following in order of increasing density– air, exhaust from chimneys, honey, water, chalk, cotton and iron.

A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?

Why does our palm feel cold when we put some acetone or petrol or perfume on it?

Suggest a method to liquefy atmospheric gases.

For any substance, why does the temperature remain constant during the change of state?

Give reasons:
A gas exerts pressure on the walls of the container.

Give reasons:
A gas fills completely the vessel in which it is kept.

What type of clothes should we wear in summer? Why?

How does the water kept in an earthen pot (matka) become cold during summer?

Why does a desert cooler cool better on a hot dry day?

Liquids generally have lower density as compared to solids. But you must have observed that ice floats on water. Find out why.

Explain why, we can easily move our hand in air but to do the same through a plank of wood, we need a karate expert.

Why are we able to sip hot tea or milk faster from a saucer rather than from a cup?

Tabulate the differences in the characterisitcs of states of matter.

Which of the following are matter?
Chair, air, love, smell, hate, almonds, thought, cold, lemon water, smell of perfume.

When extremely small particles X derived from the another of a flower were suspended in a liquid Y and observed through a microscope, it was found that the particles X were moving throughout the liquid Y in a very zig zag way. It was also observed that warmer the liquid Y, faster the particles X moved in its surface.

1. What could particles X be?
2. What do you think liquid Y is?
3. What is the zig-zag movement of particles X?
4. What is causing the zig-zag movement of particles X?
5. Name the scientist who discovered this phenomenon.
6. What does this experiment tell us about the nature of liquid Y?

Pressure and temperature determine the state of a substance. Explain this in detail.

You must have observed that the rate of evaporation increases with–

• an increase of surface area:
• We know that evaporation is a surface phenomenon. If the surface area is increased, the rate of evaporation increases. For example, while putting clothes for drying up we spread them out.
• an increase of temperature:

With the increase of temperature, more number of particles get enough kinetic energy to go into the vapour state.

In an open vessel, the liquid keeps on evaporating. The particles of liquid absorb energy from the surrounding to regain the energy lost during evaporation. This absorption of energy from the surroundings makes the surroundings cold. What happens when you pour some acetone (nail polish remover) on your palm? The particles gain energy from your palm or surroundings and evaporate causing the palm to feel cool. After a hot sunny day, people sprinkle water on the roof or open ground because the large latent heat of vaporization of water helps to cool the hot surface.

i.) Evaporation is surface phenomenon. True or false

a.) True

b.) False

c.) None of these

ii.) As temperature increases the rate of evaporation is

a.) increases

b.) decreases

c.) remains constant

d.) None of these

iii.) The rate of evaporation increases with

a.) Increase in wind speed

b.) Decrease in wind speed

c.) Does not have any effect from wind speed

d.) None of these

iv.) What happens when you pour some acetone (nail polish remover) on your palm?

v.) We are able to sip hot tea from saucer than from cup. Why?

What happens inside the matter during change of state? On increasing the temperature of solids, the kinetic energy of the particles increases. Due to the increase in kinetic energy, the

Particles start vibrating with greater speed. The energy supplied by heat overcomes the forces of attraction between the particles. The particles leave their fixed positions and start moving more freely. A stage is reached when the solid melts and is converted to a liquid. The minimum temperature at which a solid melts to become a liquid at the atmospheric pressure is called its melting point.

The temperature of the system does not change after the melting point is reached, till all the ice melts. This happens even though we continue to heat the beaker, that is, we continue to supply heat. This heat gets used up in changing the state by overcoming the forces of attraction between the particles. The amount of heat energy that is required to change 1 kg of a solid into liquid at atmospheric pressure at its melting point is known as the latent heat of fusion. So, particles in water at 0⁰ C (273 K) have more energy as compared to particles in ice at the same temperature.

The temperature at which a liquid starts boiling at the atmospheric pressure is known as its boiling point. Boiling is a bulk phenomenon. Particles from the bulk of the liquid gain enough energy to change into the vapour state. A change of state directly from solid to gas without changing into liquid state is called sublimation and the direct change of gas to solid without changing into liquid is called deposition.

i.) A change of state directly from solid to gas without changing into liquid state is called

a.) Sublimation

b.) Deposition

c.) Boiling point

d.) None of these

ii.) The direct change of gas to solid without changing into liquid is called

a.) Sublimation

b.) Deposition

c.) Boiling point

d.) None of these

iii.) The energy supplied by heat to solid is used to overcome the forces of attraction between the particles. True or false

a.) True

b.) False

c.) None of these

iv.) Define melting point and boiling point

v.) Define latent heat of fusion

 Do we always need to heat or change pressure for changing the state of matter? Can you quote some examples from everyday life where change of state from liquid to vapour takes place without the liquid reaching the boiling point? In the case of liquids, a small fraction of particles at the surface, having higher kinetic energy, is able to break away from the forces of attraction of other particles and gets converted into vapour. This phenomenon of change of a liquid into vapors at any temperature below its boiling point is called evaporation.

i.) Evaporation of liquid takes place at

a.) Boiling point

b.) Above boiling point

c.) Below boiling point

d.) None of these

ii.) Evaporation takes place at surface of liquid because

a.) They are heavy as compare to other particles

b.) They have sufficient kinetic energy to break the force

c.) They are light weight as compare to other particles

d.) None of these

iii.) During evaporation particles of liquid change into vapour

a.) From the surface

b.) From the bottom

c.) From all over the liquid

d.) None of these

iv.) Define evaporation.

v.) Explain process of evaporation

There are three states of matter – solid, liquid and gas.

Solids have a definite shape, distinct boundaries and fixed volumes, that is, have negligible compressibility. Solids have a tendency to maintain their shape when subjected to outside force. Solids may break under force but it is difficult to change their shape, so they are rigid.

Liquids have no fixed shape but have a fixed volume. They take up the shape of the container in which they are kept. Liquids flow and change shape, so they are not rigid but can be called fluid.

Gas as has indefinite shape, no fixed volume. Gas gets the shape and volume of container.

Gas has very low density hence are light. Gas can flow easily and hence are called fluid.

i.) Which of the following state of matter takes shape of container in which it is filled?

a.) Solid

b.) Liquid

c.) Gas

d.) Both b and c

ii.) Distance between particles of matter least in

a.) Solid

b.) Liquid

c.) Gas

d.) None of these

iii.) Compressibility is least in case of

a.) Solid

b.) Liquid

c.) Gas

d.) None of these

iv.) Give properties of solids.

v.) Give properties of Gases.

A matter is anything that has mass and occupies space. Pen, paper, clips, sand, air, ice, etc. are different forms of matter. Every matter is made up of small particles. These particles are so tiny that they can’t be seen with naked eyes. Let’s see about the different characteristics of particles of matter.

• All matter is made up of very small particles.
• .Particles of matter has spaces between them.
• Particles of matter are continuously moving.
• Particles of matter attract each other.

Answer the following questions by referring above paragraph.

i.) Which of following is not matter?

a.) Pen

b.) air

c.) smell of perfume

d.) None of these

ii.) Thoughts coming in our mind are example of matter. True or false

a.)  True

b.) False

c.) None of these

iii.) Which of the following is true about particles of matter?

a.) Particles of matter has spaces between them

b.) Particles of matter are continuously moving

c.) Particles of matter attract each other

d.) All of these

iv.) Give 5 examples of matter in our surroundings

v.) Enlist all properties of particles of matter