Physical States Of Matter

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PHYSICAL STATES OF MATTER Q:

Define matter and its physical states?

Matter: Anything which occupies space and has mass is called matter. Physical states of matter: Matter exists in three physical forms which are. Solid states: The state of matter which has definite shape and volume is called solid state. E.g. Book, Chair, pencil etc. Liquid state: The state of matter which has no definite shape but have definite voloume is called liquid state. e.g. water, Blood, juice. Gaseous state: The state of matter which has no definite volume and shape is called gaseous state. e.g:

Nitrogen gas, oxygen gas, hydrogen gas.

Q:

Describe intermolecular forces in 3 forms of matter.?

Intermolecular forces in Gasses: The gas molecules are very far away from each other because of weak intermolecular forces between the molecules. These forces depends upon the distance between the molecules of gasses and they gradually decreases by increasing the distance. Due to weak intermolecular forces in gasses they have no definite shape and volume. Intermolecular Forces in liquids: The liquid molecules are relatively close to each other as compared to gasses. They possess intermolecular forces which is stronger than gasses but weaker than solids. That’s why liquid have indefinite shape and definite volume.

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Intermolecular forces in Solids: The molecules of solids are very close to each other. They have a strong intermolecular force that’s why molecules in solids are compactly arranged and have definite shape and volume. Q:

what is gaseous state? Describe its Typical/ physical properties?

Gaseous state: A state of matter in which the molecules are far away from each other. They have very weak intermolecular forces.

Typical/ physical properties of gasses. Some of the typical properties of gasses are given below. 1:

Indefinite volume: Gasses have no definite volume and occupy all the available spaces.

2:

Indefinite shape: Gasses have no definite shapes but take the shape of the containers in which it is kept.

3:

Pressure: The molecule of gasses moves randomly and hit the walls of the containers. The hitting Of the molecules against the walls of the containers produces pressures. In this way, gasses exerts pressures on the walls of the containers which increases with increase in temperatures.

4:

Compressibility and expansion: Gasses can be compressed by applying pressures because they have large empty spaces between their molecules. Similarly gasses expand by decreasing pressure.

5:

Mobility: Molecules of gasses are in constant motion because of the weak intermolecular forces between their molecules.

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6:

Diffusion: The spontaneous mixing of the molecules of one gas with another at a given temperature and pressures is called diffusion. The gas molecules are constantly moving so they have the property of mixing with one another.

7:

Effusion: The escaping of the gas molecules one by one from the container through a small hole is called effusion.

8:

Density: Density is defined as mass per unit volume. (D= m/v). the volume occupied by gas possess mostly empty spaces, which increase its volume so density of a gas is very low.

Q.

States and explain boyle’s law

Boyle’s law This law states that “The volume of a given mass of gas is inversely proportional to the pressure if the temperature remains constant.” Mathematically Pα

P=k

1 v

(Constant Temperature) 1 v

(K constant of proportionality)

Multiply both sides by V So

K= PV

Boyle’s law can also be stated as “For a given mass of gas, the product of pressures and volume’s remains constant at constant temperature” Explanation:

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If P1 and V1 is the initial pressure and volume of a given mass of a gas and its final pressure and volume are P2 and V2 at constant temperature, then we can write the boyle’s law can be written as P1V1=P2V2 Conclusion: this law explains that if we increase pressure of a given gas then the volume of a gas decreases. Note: Follow example 5.1 from book. Q:

State and explain Charle’s law?

Charle’s law This law states that……… “At constant pressure the voloume of a given mass of gass is directly proportional to its absolute temperature” Mathematically: Vα T

(pressure constant)

V=K T

(K. constant of proportionality)

K=

v T

Explanation For a given mass of a gas when the initial volume is V1 and the initial temperature T1 If the temperature changes to T2 then the final volume becomes V2 the relationship can be written as. v1 T1

=

V2 T2

Note: Follow Example 5.2 from book Q:

Describe typical / physical properties of liquids?

Liquid state:

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In liquid state the intermolecular forces of attraction are strong enough as compared to gasses but weaker than solids. The liquids have indefinite shape and definite volume that’s why the liquids flows and attains the shape of the containers. Physical properties of liquids:

1:

volume and shape. Liquids have definite volume but indefinite shape that’s why it takes the shape of the containers in which it is kept.

2.

Mobility. Molecules of gases tend to flow because of its weak intermolecular force of attraction.

3.

Diffusion. Liquids like gasses diffuse and mix with each other’s. eg. Ink and water mixes with each other’s.

4.

Evaporation. The spontaneous change of a liquid into gaseous state is called evaporation. The process of evaporation in liquids occurs at all temperatures in an open container. The molecule of liquid moving with higher kinetic energy, which may overcome the forces and leave the surface of liquid. The rate of evaporation depends on  The strength of intermolecular forces  Temperature  Surface area of liquids

5.

Vapors pressures. In a close containers vapors exerts pressure on the liquids, so the pressure exerted by vapors above the liquids at a given temperature is called vapors pressures.

6.

Boiling Point. Boiling point is the temperature at which vapors pressures becomes equals to the atmospheric pressure. When the liquid is heated the kinetic energy of molecules gradually increases which increases the vapors pressures and a times comes when the vapors pressures of liquids

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becomes equal to atmospheric pressures and liquid starts boiling. Boiling points changes with changing in atmospheric pressures. 7.

Freezing points. The temperatures at which liquids freezes is called freezing point. The freezing points is the same as the melting point of all pure substance.

Q.

What are solids? Describe its typical/ physical properties.

Solid: The state of matter which have definite shape and volume is known as solid state. The particles in solids are compact with each other in a fixed pattern. Typical/ physical properties of solids: 1. Volume and Shape: Solids have a strong intermolecular force due to which it has a definite shape and volume. 2. Rigidity: The solids possess the property of rigidity, i.e. they resist the deforming forces due to hard structures and strong intermolecular forces. 3. Density: Density is defined as mass per unit volume (d= m/v). As the intermolecular forces in solids are strong, hence their molecules or particles are close to each other and their mass per unit volume is greater. Thus solids have greater density as compared to other states of matter. 4. Melting point: The temperature at which solids start changing into liquid is known as melting point. Melting points does not change and remains constant until the whole solids changes into liquids state. Melting point is the characteristic property of crystalline solids by which its purity can be checked. Q.

Describe types of solids? Types of solids: There are two types of solids depending upon the arrangement of particles. They are described below. a. Crystalline solids:

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The solids in which the particles (atoms, ions, Molecules) are arranged in a regular pattern in three dimension is called crystalline solids. Pure crystalline solids have sharp melting points. Examples. Sodium chloride (Nacl) Diamond .

b. Amorphous/ Non crystalline solids: “A” means absent and morphous means form and structure. The solids in which particles are not arranged in three dimensions are called amorphous solids. They are non-crystalline but hard like true solids while they do not have sharp melting point. Rather they melt over a range of temperature. Examples: Glass, waxes, wood etc. Q.

Define allotropes? Describe the allotropic form of carbon. Allotropes: It is derived from the Latin word “Allotropia” which mean variety. It is defined as “the different physical form of the same element which have same chemical properties but different physical properties are known as allotropes” Allotropy: The existence of an element in more than one allotropic form is called allotropy. Allotropic form of carbon: Crystalline carbon exists in three allotropic forms which are described as. 1. Diamond:  Diamond exists in cubic form in which each of the carbon atoms is tetrahedraly bonded by four covalent bond with four carbon atoms.  Since the covalent bond is very strong so diamond is hard and have high melting point.

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 Diamond is a bad conductor of electricity as the valence electrons are tightly held by covalent bonding. Uses of Diamond:  Diamond is used as a gem.  It is used for cutting of glasses  Black variety is used for boring and drilling of rocks and is also used in cutting and polishing of other gems. Note: Draw the structure of diamond from book

2. Graphite: It is derived from a word “Graphine” which means to draw or to write.  In graphite carbons atoms are arranged hexagonally in the forms of sheets.  The sheets are linked by weak attractive forces so that these sheet slides over each other’s.  Graphite is soft, lubricants and a good conductor of electricity. Uses of Graphite:    

It is used in the manufacturing of lead pencils. It is used in electrotyping. It is used in making electrodes. It is used as a lubricant for heavy machinery.

Note: Draw the structure of graphite from book. 3:

Bucky Balls     

It is the third allotropic form of carbon discovered in 1985. Their molecules contain 40-100 carbon atoms. These atoms are arranged in a hollow cage like structure called Bucky Balls. This atom after linking with each other’s assuming the shape of a football. The carbon atoms are joined together making pentagonal or hexagonal structures.

Uses of Bucky Ball. Bucky balls are used as  Super conductors  Semi-conductors  Lubricants.

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