Valentina
Matter
◆ Matter is anything thal occupies space and has mass.
◆ The distinguishing properties of matter are gravitation and inertia.
◆ Matter consists of atoms and molecules,lt generally exists in three states - Solid, liquid and gas
◆ The fourth state of matter is Plasma.
◆ Matter is found in plasma state in the central part of the sun and other stars.
◆ Plasma is the state of matter in which the particles exist in ionized state at very high temperature.
◆ The fifth state of matter is Bose Einstein Condensate.
◆ Sixth state of matter is Fermionic Condensate
States of Matter
◆ Each substance is made of tiny particles which
cannot be seen with naked eyes. These particdes bear all the properties of the substance.
◆ In solid, partides are very close to each other. Their freedom of movement is limited.
◆ In liquid, particles are relatively farther apart and have more freedom of movement than in the solid state.
◆ In the gascous state, particles remain far away from one another and freedom of movement is very hign.
◆ The difference in temperature causes the change of state.
◆ In all states, when heat is provided, the energy and movement of particdes increase, while attraction among particles decreases.
◆ The intermolecular force of attraction acting between the molecules of same substance is called cohesive force.
◆ The inter molecular force of attraction acting between the molecules of different substance is called adhesive force.
properties of Solids
● Elasticity: The property of a body by virtue of which it regain its original configuration after the removal of deforming force is called elasticity. Quartz &phosphor bronze are examples of almost perfectly elastic bodies.
● Plasticity: The property of a body by virtue of which it does not regain its original configuration after the removal of deforming force
◆ The fractional change in configuration,
ie, length, volume and shape, is called strain. Strain has no unit.
◆ The internal restoring force acting per unit area of cross-section of a deformed body is called stress
◆ Hooke's Law states that, within the limit of elasticity, the strain produced in a body is directly proportional to the stress applied to it.
◆ The minimum stress required to break a wire is called breaking stress.
◆ Steel is more elastic than rubber.
◆ Springs are made of steel.
◆ Elastic limit is the limit of stress and strain upto which a wire remains elastic,
ie, when the stret ching force is removed, the wire acquires its natural length.
Properties of Fluids
◆ A substance which begins to flow under an external force is called a fluid Liquids and gases are fluids.
◆ The ratio of mass to the volume of a body is called its density. It is a scalar quantity having SI unit kg/m³
◆ The density of water is 1000 kg/m³.
◆ The density of water is maximum at 4°c Celcius
◆ Hydrometer is the instrument used to measure density or relative density of liquid. It works on the law of floatation.
◆ The unit of fluid pressure is pascal.
◆ The presure exerted by the atmosphere is called atmospheric pressure. The unit used to measure atmospheric pressure is pascal.
◆ Aneroid barometer is used to measure atmospheric pressure. Torr& bar are other units of atmospheric pressure
Pascal's Law
◆ The pressure exerted anywhere at a point of confined fluid is transmitted equally and undiminished in all directions throughout the liquid.
◆ Hydraulic lift, hydraulic press and hydraulic breaks work on the basis of Pascal's Law.
◆ A body will float in a liquid if the weight of body is equal to the weight ofliquid displaced by the immerced part of the body
◆ lce and large icebergs float on water surface as its density is lesser than the density of water.
◆ It is easier to swim in sea water than in a river as density of sea water is greater than the density of river waler. In sea water, buoyant force is grealer than that
in river water.
Surface Tension
◆ The property of a liquid by virtue of which it tries to minimise its free surface area is called surface tension.
◆ The minimum surface area of a given amount of liquid is for spherical shape. Therefore rain
drops are spherical.
◆ The surface tension
of a liquid decreases with increase in temperature.
◆ When soap, detergent, dettol, phenyl etc, are mixed in water, then its surface tension decreases.
◆ When salt is added to water, its surface tension increases.
◆ When oil spreads over the surface of water, its surface tension decreases.
◆ The surface tension of soap solution in water is less than the surface tension of pure water. Therefore soap solution
cleans greasy strains of clothes better than the pure water.
◆ Antiseptics like dettol have low surface tension and therefore it reaches in the tiny cracks of the wound and cleans the germs and bacteria.
Capillarity
◆ The phenomenon of rising or falling of liquid column in a capillary tube is called capillarity.
◆ Water rises in narrow capillary tubes in a tree due to capillarity
◆ A blotting paper sucks the ink into their narrow tubes due to capillarity.
◆ The liquid column of water, milk etc rises in capillary tubes while mercury column falls.
Sublimation
◆ Some substances in solid state, when heated, change directly into gas without forming liquid. This phenomenon is Sublimation.
◆ Naphthalene and iodine are examples for substances that undergo Sublimation.
◆ Subllimation is an endothermic process.
◆ The reverse process of sublimation is deposition or desublimation.
◆ In sub freezing of air, water vapour changes directly to ice without first becoming a liquid.
◆ The transition from liquid to gas is called evaporation.