Matter In Our Surroundings

In ancient time, the element is classified in the form of five basic elements – the “Panch Tatva” which are air, earth, fire, sky and water

According to ancient people, living or non-living things was made up of these five basic elements.

i. faster

Particles of matter are continuously moving and as we increase the temperature, particles move faster. Their speed increases to a great extent.

ii. increases

Particles of matter are continuously moving that is, they possess what we call the kinetic energy. As the temperature increases, kinetic energy of the particles also increases.

iii. higher

The rate of diffusion of liquids is higher than that of liquids because in the liquid state, the particles move freely. There is so much space between each other. In solids, the particles are packed tightly and cannot move freely.

A piece of chalk can be broken into small particles on hammering, but it is not possible to break a piece of iron in the same fashion because the force of attraction between particles of the chalk is too weak than the force of attraction between the particles of iron. Hence we can easily break chalk by hammering but not pieces of iron.

Given:

Mass of sand (m) = 208g

Volume of water (v) = 80mL

To calculate density (p), apply the formula given:

Density = 2.6g/mL

We know that 1mL = 1cm³

Thus, the density of sand is 2.6g/cm³.

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 and can be called fluid.

Examples of Fluid:

i. River flowing

ii. Blood circulating in our body.

Solid ice floats on water because it has a lesser density than water. This means solid ice is lighter than water. The heavier water removes the lighter ice, hence ice floats to the top.

The fragrance of burning incense stick spreads all around by a physical process called diffusion. The spreading andintermixing of a substance with anothersubstance due to thecontinuous motion of the particles is calleddiffusion.

The figure is shown here:

i. lesser

The temperature at which solid melts to become a liquid at the atmospheric pressure is called its melting point. Higher the melting point of a substance, more easily the substance gets converted into a liquid which has less force of attraction between its particles.

ii. vapour

Boiling is a bulk phenomenon. Particles from the bulk of the liquid gain enough energy to change into the vapour state.

iii. Sublimation

Naphthalene undergoes the process of sublimation. Sublimation is a change of state directly from solid to gas without changing to liquid state or vice versa.

Vapourization is the process that takes place when as substance is converted from a liquid or a solid to gas. In vapourization, the change of state occurs.

Particles start vibrating in the solids because:

i. On increasing the temperature of solids, the kinetic energy of the particles increases.

ii. Due to the increase in kinetic energy, the particles start vibrating with greater speed.

To convert the temperature in celsius scale to the temperature in kelvin scale.

● 70°C = (273 + 70)K

● 343

Latent heat of fusion is the amount of heat energy required to change 1kg of a solid into liquid at its melting point. The latent heat of fusion of ice is 80cal/g.

Burns caused by the steam is much more severe than boiling water because:

i. Water vapour (steam) at 373k (100°C – boiling point) have more energy than the boiling water at the same temperature.

ii. Particles in steam have absorbed extra energy in the form of latent heat of vaporization.

iii. Hence, due to this extra energy, steam causes more burns than boiling water.

Gases can be liquefy by applying pressure and reducing temperature.

Pressure and temperature are the major factors which determine the state of matter whether it is solid, liquid or gaseous state.

The SI unit of pressure is Pascal (Pa).

Its value in 1 atmospheric pressure is:

1 atmosphere (atm) = 1.01 × 10⁵ Pa

Note: Atmospheric pressure is the pressure of air in the atmosphere. The atmospheric pressure at sea level is 1 atm.

Wet clothes dry up by the physical process of evaporation:

i. If the surface area is increased, the rate of evaporation also increases.

ii. While putting clothes for drying up, we spread them out (surface area increased)

iii. As a result, the rate of evaporation increases and wet clothes dry up fast.

Acetone is the chemical compound is present in nail polish remover.

There is a fourth state of matter- “plasma”. Plasma state is mainly responsible for the glow of the sun and the stars.

The full form of BEC is Bose-Einstein condensate. A Bose Einstein condensate is the fifth state of matter. This state does not exist under normal conditions.

All the substances around us are alike because everything around is made up of matter. The air we breathe, the food we eat, stones, clouds, water, plants, and animals – each thing is matter.

Matter is defined as anything that occupies space, mass, and volume. Air occupies space and mass. For example:

i. Take a balloon and blow air into it.

ii. We will see that balloon expands which shows that air occupies space.

iii. Weight the balloon and the mass difference.

iv. The difference shows that air occupies mass.

v. Hence, air can be considered as matter.

Solid state of matter has the tendency to maintain its shape when subjected to outside force:

For example: A rubber band (solid) changes shape under outside force and regains the same shape when the force is removed.

Diffusion is the process through which the ink is dissolved into the whole water. Ink has lesser density. Hence, it spreads throughout the water.

Dry air is heavier than wet air because:

i. Dry air has nitrogen (N₂) and a molecule of oxygen.

ii. Wet air has a water molecule (H₂O).

iii. Nitrogen and a molecule of oxygen in dry air are heavier than the water molecule of wet air.

The diffusion of gases helps us in detecting the leakage of LPG gas:

i. The gases have large space between its particles.

ii. The speed of the particles is also much faster.

iii. This shows that the gases diffuse very fast into other gases.

(i) 65^° C = (273 + 65)K

● 338K

(ii) 300^° C = (273 + 300)K

● 603K

No dry ice is not same as ordinary ice.

i. Solid carbon dioxide is known as dry ice.

ii. It is stored under high pressure.

iii. Solid CO₂ gets converted directly to gaseous state on decrease of pressure without changing into liquid state.

iv. Hence, solid CO₂ is called dry ice.

Humidity is the amount of water vapour present in the air. If the amount of water in air is already high, the rate of evaporation decreases. This leads to a decrease in humidity too.

Plasma state consists of super energetic and super excited particles. Some examples are:

i. The sun and the stars glow because of the presence of plasma in them.

ii. The plasma is created in the stars at very high temperature.

iii. The fluorescent tube and neon sign bulbs consist of plasma.

Yes, solids diffuse. On heating the solids (by increasing the temperature), the following changes occur:

i. The kinetic energy of the particles increases.

ii. The particles start vibrating with greater speed.

iii. As a result, the particles leave their fixed positions and start moving freely.

iv. It changes to liquid state or gaseous state.

To prove: Diffusion becomes faster with the increase in temperature.

Activity:

i. Take a beaker A and beaker B.

ii. Pour hot water in beaker A and cold water in beaker B.

iii. Now, put a drop of ink in beaker A and beaker B.

Observations: We will observe that in beaker A, the ink spreads throughout the water faster than in the case of beaker B.

Conclusion: Hence, this activity proves that diffusion becomes faster with increase in temperature.

1kg of sand is denser than 1kg of cotton.

Explanation: As we know that mass of 1kg cotton is larger than that of 1kg sand.

From the formula:

Density α Mass

As we can observe that density is directly proportional to mass. Larger is the mass, greater will be the density and vice versa. Hence, 1kg sand whose mass is larger will be more denser.

Cotton floats on water because:

i. Cotton is a solid which has minute (porous) holes.

ii. The holes trap air inside themselves.

iii. As a result, the overall, density of cotton becomes less than water.

iv. Being lighter than water, cotton floats on water.

In liquids:

i. The force of attraction between the constituent particles is lesser.

ii. The rate of diffusion of liquids are higher than that of solids.

iii. Hence, the particles of liquid move freely.

iv. They have greater space between each other as compared to the particles in the solid state.

v. Due to large space in the liquid, their particles held together less firmly as compared to solids.

Difference between gas and vapour:

i. 273K = (273-273)^°C

● 0^° C

At 0^°C, water can exist as both solid and liquid.

ii. 373K = (373-273)^°C

● 100^°C

At 100^°C, water can exist as both liquid and gas.

i. Solid

The force of attraction between the constituent particles of solid is strongest. The particles are closely arranged and tightly packed.

ii. Gases

The force of attraction between the constituent particles of gases is weakest. In the gaseous state, the particles move freely and randomly at high speed.

Yes, sugar and salt are solids.

As we know that solids are rigid and have a fixed shape and volume.

i. It is given that sugar and salt when kept in jars, take the shape of the jar.

ii. But each granule of salt and sugar remain in their fixed shape and volume.

iii. The shape and volume of each granule do not change at all. Hence, they are solids.

A balloon when kept in sun, bursts after some time because:

i. As we know that on increasing the temperature, the kinetic energy of the gases increase.

ii. When the balloon is kept in the sun, due to sun’s heat (temperature increases), the kinetic energy of the gaseous particles also increases.

iii. As a result, the balloon expands and continues to expand in the sun’s heat.

iv. There comes a point when the balloon bursts.

Solids are generally denser than liquids and gases because:

i. The space between the constituent particles of solid is less than that of liquids and gases.

ii. The force of attraction between the particles is maximum.

iii. Hence, large mass is concentrated in a very small volume.

iv. Larger will be the mass, greater will be the density.

v. In case of liquids and gases, there is so much space between the particles.

vi. Hence they don’t have large mass which is concentrated in a very small volume.

vii. So the density of solids is general more than liquids and gases.

Diffusion of gases in water is essential:

i. The gases from the atmosphere diffuse and dissolve in water.

ii. The gases especially oxygen and carbon dioxide are essential for the survival of aquatic animals and plants.

iii. The aquatic animals can breathe under water due to the presence of dissolved oxygen in water (diffusion of gases of atmosphere and water)

iv. Thus, we may conclude that diffusion of gases in water is essential for the survival of aquatic animals and plants.

High compressibility property of gas:

i. Gases are highly compressible.

ii. Due to the high compressibility, large volume of gas can be compressed into a small cylinder and transported easily.

iii. The liquefied petroleum gas (LPG) cylinder that we use in our home for cooking is a compressed gas.

iv. The oxygen supplied to hospitals in cylinders is also a compressed gas.

v. Compressed natural gas (CNG) that we used as fuel in vehicles these days is also a compressed gas.

The melting point is defined as the temperature at which a solid melts to become a liquid at the atmospheric pressure. The melting point of ice is 273.16K. This means that at 273.16K temperature, the ice melts and starts converting to liquid water.

On increasing pressure:

i. On increasing pressure, particles of matter come closer.

ii. If pressure is increasingly applied on a gas, particles of the gas come more closer and a stage is reached when gas may change into liquid.

iii. If pressure is increasingly applied on a liquid, it will change into liquid

On reducing pressure:

i. On reducing pressure, particles of matter expand.

ii. If reducing pressure is applied on a liquid, it will change into gas.

iii. If reducing pressure is applied on a solid, it will change into liquid.

It is advisable to use pressure cooker at higher altitudes for cooking food because:

i. A liquid boils only when its vapour pressure is equal to the atmospheric pressure.

ii. At high altitudes, the atmospheric pressure is very low.

iii. This causes the water to boil at a lower temperature which will take a lot of time for food to be cooked.

iv. A pressure cooker stops the boiling of water at lower temperature.

v. As a result, food cooks quickly.

On a hot sunny day, we feel pleasant sitting under a tree because:

i. As we know that tree has lot of leaves. Leaves continuously loss water through their small pores present in them.

ii. When this lost water from tiny pores comes in contact with the surface of leaf, the water evaporates.

iii. This evaporation causes cooling effect.

iv. This makes the surrounding cool.

i. (a) Plasma is found in the stars because of very high temperature. The plasma state consists of highly super excited and energetic particles. The sun and the stars glow mainly because of the presence of plasma in them.

(b) The force of attraction between the constituent particles of solid is strongest. The particles are closely arranged and tightly packed. Hence they have strongest intermolecular forces.

(ii) CH₄ gas would diffuse most rapidly because mass of CH₄ is least among all the given gases. Diffusion is inversely proportional to the mass of the gas. Lesser is the mass, higher will be diffusion which means lighter gases diffuse faster. Hence, CH₄ being a lighter gas would diffuse faster.

When the ice is at 0^° Celsius, the temperature of the system remains constant because the temperature (heat) is used up already to change the state of matter from solid to liquid. This phenomenon is known as latent heat of fusion.

To show that the rate of diffusion of liquids decreases with increase in density of the liquids:

Activity:

i. Take two beakers and pour some water in them.

ii. Pour some honey in first beaker and pour small drops of ink in another beaker.

iii. Leave both the beakers untouched for a while.

Observations: We will observe that the ink whose density is low gets mixed easily and spreads throughout the water. On the other hand, honey whose density is high does not get mixed and takes more time to dissolve.

Conclusion: We conclude that rate of diffusion of liquids decreases with increase in density of the liquids.

To prove that the gases are highly compressible as compared to liquids:

Activity:

i. Take two 100mL syringes and close their nozzles by rubber corks as shown in the figure below.

ii. Remove the pistons from all the syringes.

iii. Now fill water in the second syringe and leave the first syringe untouched.

iv. Now insert the pistons back into both the syringes.

v. Now try to compress the content of each syringe by pushing the piston.

Observations: We will observe that the syringe with gas is easily pushed in as compared to that of the syringe with water.

Conclusion: We will conclude that gases are highly compressible as compared to liquids.

To determine the boiling point of water:

Activity:

i. Take small amount of water in a beaker and suspend a thermometer so that its bulb (lower part) is in contact with the ice.

ii. Put a glass rod in the beaker and start heating the beaker till the water starts boiling.

iii. Note the temperature when the water converts into gaseous state.

Conclusion: The temperature at which the water starts boiling at the atmospheric pressure is called boiling point of water.

To determine the melting point of ice:

Activity:

i. Take about 150 g in beaker and suspend a thermometer so that its bulb (lower part) is in contact with the ice.

ii. Start heating the beaker at a very low flame.

iii. Note the temperature when the ice starts melting.

Conclusion: The temperature at which the ice starts melting into liquid state is called melting point of ice.

Pressure:

On increasing pressure:

i. On increasing pressure, particles of matter come closer.

ii. If pressure is increasingly applied on a gas, particles of the gas come more closer and a stage is reached when gas may change into liquid.

iii. If pressure is increasingly applied on a liquid, it will change into liquid.

On reducing pressure:

i. On reducing pressure, particles of matter expand.

ii. If reducing pressure is applied on a liquid, it will change into gas.

iii. If reducing pressure is applied on a solid, it will change into liquid.

Temperature:

On increasing temperature:

i. The kinetic energy of the particles increases.

ii. Due to the increase in kinetic energy, the particles start vibrating with greater speed.

iii. As a result, the particles leave their fixed positions and start moving freely.

iv. If temperature is increasingly applied on solid, it will change into liquid state.

On decreasing temperature:

i. On decreasing the temperature of any state, the particles come closer:

ii. If we apply reducing temperature on gas, it will change into liquid.

iii. If we apply reducing temperature on liquid, it will change into solid.

Ammonia s strong gas which has a very pungent irritating smell.

i. When the student spilled a bottle of ammonia, the diffusion of gases take place.

ii. The speed of the gases particles is very high and have very large space between them.

iii. As a result, the gases diffuse very fast with other gases.

iv. Hence, smell of ammonia was filled with whole laboratory.

i. Evaporation is the phenomenon which is associated with disappearance of water.

ii. Her mother suggested Neha to switch on the fan because water will evaporate faster in the presence of high amount of air coming from the moving fan. As a result, water will evaporate quickly and the floor will be dried very fast.

iii. Her mother is aware and concern.

1L = 1dm³ where “dm” stands for decimetre.

1L = 1000mL where “mL” stands for mililitre.

1mL = 1 cm³ where “cm” stands for centrimetre.

The correct option is (d) because as we know that kinetic energy of the gases is maximum, liquid is intermediate and solids is minimum. Hence, the order is:

Hydrogen (gas) > honey (solid but has high density than water) > water

It is given that kinetic energy of particles of water in three vessels X, Y and Z are E_x, E_y and E_z respectively. As we know that on increasing the temperature, kinetic energy of the particles also increases. Hence, the temperature of the water in the three vessels follows in the order:

T_X > T_Y > T_Z

A sponge has minute holes present in them. The air is trapped in these holes. When we press the sponge, the air is expelled out and we are able to compress it easily.

Particles in a solid move farther apart on heating - A metal rod expands on heating, when we increase the temperature. The kinetic energy of the particles increases. As a result, the particles leave their fixed positions and start moving freely.

Different particles of different elements have different masses. A gold bracelet (has large mass and density) is much heavier than an identical silver bracelet (has lower density and mass).

Gas particles always spread out to fill the space available to them. For example: It is easier to squash a balloon filled with air than a balloon filled with water.

Gas particles are father apart than liquid particles. For example: You can smell dinner cooking in the kitchen when you are in your bedroom.

A is gas, B is sold and C is liquid.

Sublimation is a change of state directly from solid to gas without changing to liquid state or vice versa. Hence, the given statement is completely wrong.

As we increase the temperature of any state, particles expands:

i. If we apply increasingly temperature on solid, it will change into liquid.

ii. If we apply increasingly temperature on liquid, it will change into gas.

iii. As we decrease the temperature of any state, the particles come closer:

iv. If we apply reducing temperature on gas, it will change into liquid.

v. If we apply increasingly temperature on liquid, it will change into solid.

In Kelvin scale:

For 25^°C:

● 25^°C = (273.16 + 27)K

● 298.16 K

For 45^°C:

● 45^°C = (273.16 + 45)K

● 318.16 K

In Fahrenheit scale:

For 25^°C:

Apply the formula:

Temperature in Fahrenheit=Temperature in celsius

Temperature in Fahrenheit

● Temperature in Fahrenheit = 77^°F

For 45^°C:

Apply the formula:

Temperature in Fahrenheit=Temperature in celsius

Temperature in Fahrenheit

● Temperature in Fahrenheit = 113^°F

The non SI unit of temperature is degree celsius and its SI unit is Kelvin.

The non SI unit of length is centimetre and its SI unit is metre.

The non SI unit of pressure is PSI (per square inch) and its SI unit is Pascal.

The non SI unit of mass is kilogram and its SI unit is kilogram.