( By. Ghanshyam kr. Chaudhary)
Chapter: 1 Matter in our surrounding.....
Matter: It is defined as anything that occupy some space and having definite mass/volume is known as matter.
States of Matter:
- The physical states of a matter are :
(i) Solid,
(ii) Liquid,
(iii) Gas.
(iv) plasma,
(v) Bose einstein condensate.
(Note: The main physical states of a matter are : Solid,Liquid,Gas.)
(i) Solid State :
Characteristics of solid states are :
(a)Have definite shape.
(b) Have distinct boundaries.
(c) Have rigidity and incompressibility.
(d)Have definite volume.
Example : ice, brick, and metals like iron, gold, copper etc.
Qus. why a rubber band is considered as solid?
Ans: Rubber band is considered as solid because it can change its shape under force and regains its shape when force is removed. If excessive force is applied, it breaks.
(ii) Liquid State :
The characteristics of liquid state are :
(a) Have fluidity i.e.,they are not rigid.
(b) Low compressibility.
(c) No definite shape and boundaries. i.e They take the shape of the vessels in which they placed.
(d) Have definite volume.
Example : Water,oil like Diseal, petrole etc.
(iii) Gaseous State :
The characteristics of gaseous sgtate are :
(a) Have fluidity more than liquid.
(b) Have high compressibility.
(c) Have no definite shape, size and boundaries.
(d) Have no definite volume.
Example : air or gases like Nitrogen, oxygen,etc.
Qus(1) : Classify human bodies into three states of matter?
Ans: We can classify human body into three states of matter
are as follows:
(i) Bones and teeth are solids.
(ii) Blood and water present in our body are liquids.
( Note: There is 75% of water present in our body. )
- Particles of matter are continuously moving i.e., they possess kinetic energy. As the temperature rises, particles moves faster because kinetic energy of the particles increases.
- Particles of matter have space between them:When we make tea, coffee or lemonade (nimbu pani), particles of one type of matter get into the space between particles of the other. This shows that there is enough space between particles of matter.
- Particles of matter attract to each other : i.e
Ans: The space between the particles and kinetic energy of particles is minimum in solids, intermediate in liquids and maximum in gases.
( note: kinetic energy of particle is varies on their space between the constituent particle. )
solid -------> liquid --------> Gas
( low ) ( intermediate ) ( high )
Qus(4) : Arrange solid, liquid, Gas into increasing order of the force of attraction?
Ans: The force of attraction between the particles is strongest in solids, intermediate in liquids and weakest in gases. Because The force of attraction betwwen to particle or body is calculated by the formula
F = G M1×M2
R^2
where:
G is a constant and is known as Gravitational constant.
Value of G = 6.67 × 10-11 Nm2/kg2 G is called universal gravitational constant.
M1 = mass of first particle/object.
M2 = mass of second particle/object.
R^2= Distance between two particle/ object.
( note: The force of attraction is depend on distance between the constituent particle or the distance betwwen to particle is very very small in solid, intermediate in liquid or greater in gas. )
Qus(5) : Why the gases are more fluidity than the other states of matter?
Ans: Gases have more fluidity than the other state of matter because the space between the constituent particle of gases is much more than other hence it is fludity
in nature.
The space of constituent particle is varies on
Gases state -------> Liquid state --------> solid state.
( More ) ( intermediate ) ( low )
Qus(6) : why our houses is not flow as the water or gases?
Ans: Because our houses is made up of brick which is solid or distance between the constituent particle of solid is very negligibleor less hence the force of attraction is maximum that's why our houses is not flow as the other state of matter.
Qus(7) : write to suggest a state of matter which exist in three states of matter?
Ans: water example of liquid state which exist in three state of matter like solid in form of ice, liquid in form of
drinking water or gases in the form of vapour.
Qus(8) : what is melting point? explain with a suitable example?
Ans: Melting Point :
It is defined as the temperature at which a solid melts to form liquid at atmospheric pressure is called its melting point.
Example:
Melting point of ice is 273.15 K or 0º C.
( Note : SI UNIT of temperature is kelvin or it is represented by K. )
Qus(9) : what is latent heat of fusion.?
Ans: Latent Heat of Fusion :
It is defined as the amount of heat required to change or convert 1kg solid to its liquid state (at its melting point) at atmospheric pressure is known as latent heat of fusion.
Qus(10) : Defined boiling point? with suitable example?
Ans: Boiling Proint :
The temperature at which a liquid boils to form vapours at atmospheric pressure is called its boiling point.
Example:
Boiling point of water is 373 K or 100°C .
( Note: To convert the temperature of a substance from °C to K( kelvin ) with the help of formula:
K = 273.15 +°C
Where:
K is temperature in kelvin.
C is temperature in °C
Qus(11) : If the boiling point of alcohol is 78°C then, what its boiling point on kelvin?
Ans: Boiling point of alcohol in °C = 78
Boiling point of alcohol in kelvin = ?
therefore, using
K = 273.15 +°C
K = 273.15 +78 = 351.15 K
means the boiling point of alcohol is 351.15 in kelvin( K )
Qus(12) : Defined latent heat of vapourization?
Ans: Latent Heat of Vapourization :
The amount of heat required to change or convert 1 kg liquid to its gaseous state (at its boiling point) at atmospheric pressure.
Qus(13) : What effect yoh observ when temperature rise on states of matter?
Ans: When we rise the temperature following effect observ on the states of matter i.e on applying temp. solid convert to liquid, on further applying temperature liquid will change to vapour( gas ) similarly when we fall down the temperature gas ( vapour ) convert to liquid or further liquid convert to solid.
Example : ice, ice change its physical states on applying temoerture i.e it convert to liquid or liquid convert to vapour or gas on applying temperture.
Qus(14) : How can we liquify a gas?
Ans: we can liquify a gas with decrease in temperature and increasing the pressure.
Gas = Decrease in temperture + Increase in pressure
can be liquify.
Qus(15) : What is sublimation?
or
Defined the process of sublimation?
Ans: Sublimation :
It is defined as The process by which a solid substance directly change into vapours on heating and the vapours convery into solid on cooling without passing through the liquid state is called sublimation.
Example:
When camphor or ammonium chloride is heated it convert solid to gases state without change into liquid state.
Qus(16) : what is evaporation?
Ans: Evaporation is defined as the surface phenomenon by which a liquid substance changes into vapours at any temperature below its boiling point is called evaporation.
( Note: it occuer because particle of liquid have higher kinetic energy than others, so they break. The forces of attraction between the particles & escape from the surface of liquid in the form of vapours. )
Qus(17) : Write the factor which affect evaporation?
Ans: evaporation is affected by the following factor:
Rate of evaporation depends on :
- Exposed surface area :
Higher the surface area, higher the rate of evaporation.
- Increase in temperature :
With the Increases in temperature kinetic energy of particles or molecules will also increase hence the rate of evaporation increases. So we can say that the rate of evaporation is directly proportional to the increase in temperature.High temperture,higher the rate of evaporation.
- Humidity :
When the humidity of air (degree of dampness of air) is low, evaporation rate is dicreased. Hence we can say that the rate of evaporation is inversly varies with humidity.More humidity, less evaporation.
- Wind :
When speed of wind increases, rate of evaporation also increases.
- When we put acetone on our hand, it gets evapourized by taking heat from our hand and our hand feels cool.
- We should wear cotton clothes in summer to keep cool and comfortable as cotton is good absorber of water, so it absorbs the sweat from our body and exposes it to air for evaporation of sweat cause cool our body.
- Often people sprinkle water on ground during summer. This water takes heat from ground and surrounding air to evaporate, which cause surrounding atmospher cool.
""Radhe Radhe""
।। Bolna Padega ।।
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