Diffusion

Diffusion

The spreading and mixing of particles of matter from one substance to another is called diffusion. This diffusion takes place due to the motion of particles from one substance to another.

1.Diffusion is fast in gases whereas in solids it is very slow: diffusion is faster in gases as the particles of gases move more freely, the force of attraction between the molecules are less so they can move independently. In case of liquids the movement of molecules is restricted so they move little slower than gases. In case of solid the intermolecular force is very strong so they rarely move, thus making diffusion very slow in case of solids.

2.Rate of diffusion increases with increase in temperature: when a substance is heated the particles of that substance get kinetic energy so they start moving rapidly making diffusion faster.

Diffusion explained with example:

Diffusion in gases:

1.      Smell of food cooked in kitchen reach us in other room: when food is cooked the gases released from the food contain smell with it. These gas particles containing aroma mix up with the surrounding air and rapidly move ahead to reach us.

2.      Smell of perfume spread due to diffusion.

3.      Smell of warm food can be observed from a distance but to smell the same food when cold we have to get close to it.

Diffusion in liquids:

1.      Crystal of potassium permanganate when placed in water and left undisturbed mixes with each other is due to diffusion. The particles of potassium permanganate spread in water due to diffusion.

2.      A drop of ink spreads in water as the small particles of ink move inside water due to diffusion.

Diffusion in solids:

1.      Two metal blocks when left together close to each other the particles of both diffuse with each other

2.      When blackboard scribbled with chalk is left that way for some time, we cannot clean the board quickly this happens because the particles of chalk diffuse in board and so it gets difficult to remove chalk particles from the board.

triangles solution

Solutions triangles

Fill in the blanks

1.     Less than

2.     More than

3.     180^o

4.     Acute

5.     Obtuse

6.     60^o

Which triangles are feasibles

1.     6+1=7

The sum of two smaller side equal to third therefore it cannot be a triangle (Sum of two angles are always more than third side)

2.     3+2=5

5<6

The sum of two smaller side less than third therefore it cannot be a triangle (Sum of two angles are always more than third side)

3.     80+70+40= 190

Sum of three angles is not equal to 180^o. Therefore it cannot be a triangle.

4.     170+6+4=180

    Sum of three angles is equal to 180^o. Therefore it is a triangle.

Solve

1.     Right angle = 90

Given angle=30

90+30+ 3^rd angle=180

120+ 3^rd angle=180

3^rd angle= 180-120

3^rd angle = 60

2.     One of the equal angles =40

∠A+∠B+∠C=180

40+40+∠C=180

80+∠C=180

∠C=180-80

∠C=100

3.     Unequal angle of isosceles triangle=30

∠A+∠B+∠C=180

30+∠B+∠C=180

∠B+∠C=180-30

∠B+∠C=150

∠B=∠C=150/2

∠B=∠C=75

4.     ∠A+∠B+∠C=180

80+20+∠C=180

100+∠C=180

∠C=180-100

∠C=80

5.     Right angle= 90

Isosceles triangle= two other angles are equal

∠A+∠B+∠C=180

90+∠B+∠C=180

∠B+∠C=180-90

∠B+∠C=90

∠B=∠C=90/2

∠B=∠C=45

6.   

   

No of triangles= 32

Different ways in which the marked angle can be named:

∠ACE, ∠ACJ, ∠ACI

∠GCE, ∠GCJ, ∠GCI

∠HCI, ∠HCJ, ∠HCE

∠ICH, ∠ICG, ∠ICA

∠JCH, ∠JCG, ∠JCA

∠ECH, ∠ECG, ∠ECA

7. vertices- A, B, C

Sides- AB, BC, CA

Acute angles- ∠ABC, ∠ACB

Obtuse angles- ∠BAC

triangles questions

Triangle questions       class V

Fill in the blanks

1.  Acute angle is …………………… 90^o

2.   Obtuse angle is …………………….90^o

3.  Straight line measures…………………….

4.   Equilateral triangle is always………………………….(acute/obtuse)

5.    Other angles of Right triangle is never…………….…………….(acute/obtuse)

6.    Every angle of an equilateral triangle is……………………

Which triangles are feasible?

1.     1Sides – 6cm, 7cm, 1cm

2.     2Sides 6cm,3cm,2cm

3.     3Angles- 80^o, 70^o, 40^o

4.     4Angles – 170^o, 6^o, 4^o

Solve

1.     One angle of a right triangle is 30^o. Find the other angles.

2.     One of the equal angles of an isosceles triangle is 40. Find all the angles.

3.     The unequal angle of an isosceles triangle is 30. Find the other angles.

4.     Two angles of a triangle are 80 and 20. Find the third angle.

5.     Find the Angles of an isosceles right triangle.

6.     How many triangles are in the figure? In how many ways can the marked angle be named?              

     

                     

7.   Name the   a. vertices    b. sides

c. obtuse angles       d. acute angles. 

solutions in the next post


http://manishieducare.blogspot.com/2013/12/triangles-solution.html

7. 

Atoms and subatomic particles

Structure of atom

Atom and molecules are the building blocks of matter. The different matter around us are due the different atoms and molecules that combine together to form those substance. The atoms of different matter are different which have different number of electrons, protons and neutrons. Earlier it was a conception that these small particles are indivisible, but later through experiments and calculations it was concluded that atoms are also divisible and they have structural body.

The components which form an atom are: electrons, protons, and neutrons, these smaller particles are called subatomic particles. Among these subatomic particles electrons are negatively charged, protons are positively charged and neutrons are neutral, that means neutrons are charge less.

Protons and neutrons are present at the centre of atom, this centre is called nucleus and the electron is outside the nucleus.

In an atom the number of electrons and protons are equal thus the overall charge of an atom is zero, on comparing the mass the proton and neutron carries the total mass of an atom in the nucleus and the electron which travels in a circular path around the nucleus contributes nothing to the mass of atom as its mass is almost negligible.

Presence of charged particles around us

When we rub inflated balloon in dry hair, balloon is attracted towards woollen cloth. When we rub glass rod with silk cloth, glass rod attracts an inflated balloon. These two experiments prove that balloon when rubbed with dry hair get electrically charged such that when bought in contact with woollen cloths both attract each other. Thus we can say that charged particles are present in the atoms.

Characteristics of electron, proton and neutron

Characteristics of electron:

        I.            Mass of electron: Absolute mass of electron is 9×10^-28grams. It is 1/1840 of mass of one atom of hydrogen.

      II.            Charge of an electron: Absolute charge of an electron is 1.6 × 10^-19 coulomb negative charges.  1.6 × 10^-19 coulomb is the smallest charge carried by any particle, so it is also called one unit charge.

Characteristics of proton:

        I.            Mass of proton: Absolute mass of proton is 9×10^-24grams. It is the mass of one atom of hydrogen.

      II.            Charge of a proton: Absolute charge of an proton is 1.6 × 10^-19 coulomb positive charges. This is equal and opposite charge to that of an electron. It is the smallest positive charge carried by any particle, so it is also called one unit charge.

Characteristics of neutron:

        I.            Mass of neutron: Absolute mass of electron is 9×10^-24grams. It is equal to the mass of a proton

      II.            Charge of a neutron: neutron has no charge, it is electrically neutral.

Discovery of electron, proton, and neutron:

Discovery of electron:

The existence of electron in an atom was discovered by J.J.Thomson.

Experiment:

A discharge tube was taken with gas in it at a very low pressure.

Electricity at high voltage was passed through it.

Observations:

Stream of minute particles were given out by the cathode (negative electrode through which current is passing).

These streams of particles are called cathode rays because they come out of cathode.

Since the particles move out and away from cathode (negatively charged), it was concluded that these particles are negatively charged.

Since all different kind of gases emit cathode rays so it was concluded that all atoms contain negatively charged particles.

The mass and charge of these particles does not depend on the gas.

Later these negatively charged particles were called electrons.

Discovery of proton:

The existence of proton in an atom was discovered by E.Goldstein. the presence of electrons already proved that there are some positive particles present in an atom that keep an atom electrically neutral.

Experiment:

A discharge tube was taken with gas in it at a very low pressure.

Electricity at high voltage was passed through it.

Observations:

Stream of heavy particles were given out by the anode (positive electrode through which current is passing).

These streams of particles are called anode rays because they come out of anode.

Since the particles move out and away from anode (positively charged), it was concluded that these particles are positively charged.

The mass and charge of these particles depend on the gas used in the discharge tube

Later these positively charged particles were called protons.

Discovery of neutron:

The existence of neutron in an atom was discovered by James Chadwick.

After the discovery of protons and electrons, the charges present in atom and the neutral behaviour of atom was explained, but the extra mass of atom other than the mass of proton was still to be explained. This problem was solved by the discovery of another subatomic particle. This particle was neutron which had mass but was charge less.

Characteristics of particles of matter

Characteristics of particles of matter:

1.      Very small in size.

2.      Have spaces between them

3.      Particles are constantly moving

4.      Particles attract each other

The characteristics of particles can be discussed by experiment.

Particle of matter are very small: we take a beaker full of water and add small amount of ink to it. Ink diffuse in water and spreads uniformly. When more water is added the colour dilutes, this is because few drop of ink is composed of millions of small particles which keep on spreading in large amount of water. 

Particles have space between them: we take a beaker full of water and add small amount of ink to it. Ink spreads uniformly between the spaces present between the particles of water.

Particles are constantly moving: we take a beaker full of water and add small amount of ink to it. Ink spreads uniformly after some time even when we leave it undisturbed, this happens because the particles of matter are constantly moving. The same can be observed with essence sticks, as the gases spread from one corner of room to the whole space.

Particle of matter attract each other: the force of attraction between the particles of same matter is called cohesion. This cohesion is different for different material. Like for liquid and gases they are less but for solid they are large. That is why it is difficult to break apart a solid but it is easier of liquids. We can move our hand through liquid and gases but not through solid. We cannot break iron but ban easily break chalk as cohesive force between the particles of iron is much larger than that of chalk.

  

Matter is made of particles

Every matter is made up of very small particles. These tiny particles are extremely small which cannot be seen even with high power microscope. These small particles that form other objects are called atoms and molecules.

How to prove that matter is made up of small particles.

We can easily observe that matter is composed of small particles by mixing two different things and noticing the two dissolve in each other.

1.      Dissolving solid in liquid

2.      Dissolving liquid in liquid

3.      Mixing two gases

Dissolving solid in liquid: To discuss this we will take

 Potassium permanganate, a purple coloured solid crystalline substance and water, a colourless liquid. When potassium permanganate is added to beaker full of water and leave it as it is, slowly the colour of water will change to purple, this is because the molecules of potassium permanganate separate from one another and diffuse in water. Here diffusion means that the molecules of potassium permanganate spread in water to make a uniform solution.

Dissolving liquid in liquid: To discuss this we will take

 Blue coloured ink and water. When ink is added to beaker full of water and leave it as it is, slowly the colour of water will change to blue, and this is because the molecules of ink diffuse in water. This means that ink and water both are made of small particles.

Mixing two gases: let’s take 2 test tube

One with colourless gas and other with bromine vapour, a red-brown coloured gas when the two test tubes are joined after some time the content of both gases mix with each other. Content of both tubes are made of small particles that diffuse in each other

This diffusion phenomenon gives us two conclusions:

1.      Matter is made of two particles.

2.      These particles have kinetic energy and they are constantly moving.

Matter is made of particles

Matter is made of particles

Every matter is made up of very small particles. These tiny particles are extremely small which cannot be seen even with high power microscope. These small particles that form other objects are called atoms and molecules.

How to prove that matter is made up of small particles.

We can easily observe that matter is composed of small particles by mixing two different things and noticing the two dissolve in each other.

1.      Dissolving solid in liquid

2.      Dissolving liquid in liquid

3.      Mixing two gases

Dissolving solid in liquid: To discuss this we will take

 Potassium permanganate, a purple coloured solid crystalline substance and water, a colourless liquid. When potassium permanganate is added to beaker full of water and leave it as it is, slowly the colour of water will change to purple, this is because the molecules of potassium permanganate separate from one another and diffuse in water. Here diffusion means that the molecules of potassium permanganate spread in water to make a uniform solution.

Dissolving liquid in liquid: To discuss this we will take

 Blue coloured ink and water. When ink is added to beaker full of water and leave it as it is, slowly the colour of water will change to blue, and this is because the molecules of ink diffuse in water. This means that ink and water both are made of small particles.

Mixing two gases: let’s take 2 test tube

One with colourless gas and other with bromine vapour, a red-brown coloured gas when the two test tubes are joined after some time the content of both gases mix with each other. Content of both tubes are made of small particles that diffuse in each other

This diffusion phenomenon gives us two conclusions:

1.      Matter is made of two particles.

2.      These particles have kinetic energy and they are constantly moving.

States of matter

Three states of matter

Now we will discuss the three states of matter : solid, liquid and gas.

Properties of solid:

·         Fixed shape and volume

·         Have high density

·         Do no flow

·         Certain solid can be compressed but not much, eg rubber

Properties of liquid:

·         Have fixed volume but don’t have a ffixed shape

·         They have less density than solid

·         Flow easily

·         Cannot be compressed

Properties of gases:

·         Have no fixed shape or volume

·         Have very low density

·         Flow easily

·         Can be compressed easily

Comparing the properties of solid, liquid and gases

Shape: either it is a book, chair or table every solid have a fixed shape, their shape remains the same wherever we place it. But in case of liquid and gases they do not have a fixed shape because they change their shape according to the container in which they are stored

Volume: solid and liquid have fixed volume, that means that they will occupy a certain required space, a iron ball of volume 100cubic cm when melted and moulded in another shape will still occupy the same space, similarly when 1l of water when kept in a jar or in a tub may change its shape but in both cases it will occupy same 1l of space. In case of gases the gas can be compressed in a small space by applying pressure, LPG and CNG is an example of large amount of gas compressed in small cylinders.

Density: density of solid is maximum, liquid has comparatively less density and gases have even more density. This difference in density is due to gap in molecules of atoms, the atomic gap in case of solid is negligible. They are very closely packed and hence the density is high, the molecules of liquid are comparatively far with each other and gases are even farther so the density of liquid are less and gases even more less.

Flow: the flow of solid is zero, this means that solid cannot flow, this is because they have a defined shape, their molecules are compact without any gap between them, they have high force of attraction among their molecules which keep them from flowing. But in case of liquid and gases they have a defined shape, their molecules are less compact means they are a bit far and the force of attraction between their molecules are less so they can easily flow. Due to these factors gases can flow even more easily when compared to liquids.

Compression: there are a few solids like rubber and sponge that can be compressed under pressure, rubber is elastic in nature so it can change its shape when force is applied, on the other hand sponge has minute pores from which air gets squeezed out when we press it thus changing its shape. Liquid cannot be compressed although it has space between its molecules, gases have lots of space between them so when compressed  they gets squeezed and decrease in volume.

Why salt, elastic and sponge are called solid?

Although when placed in a container salt and sugar take their shape but the single particle of salt have its definite shape which cannot be changed.

Rubber is elastic in nature so it can change its shape when force is applied on it

Sponge has minute pores from which air gets squeezed out when we press it thus changing its shape.

Matter: An introduction

What is matter?

Anything that has volume and mass is called matter. Substance either as light as a feather or as hard as a brick all are matter. Anything which can flow as water or smoke all are matter.

Oxygen and hydrogen are gases, they have volume and mass which is negligible. Water, milk or juice have mass and they occupy space. Sand or brick they have mass as well as they occupy space.

All these are matter.

When we look around us everything that we see is matter. In the morning from using toothbrush till the night while we go in our beds all are matter.

                                                            

On the basis of physical properties matter is classified in three forms: Solid, liquid and gas

Solids are those substance which have fixed shape and volume.

Liquid are those substance which have fixed volume but no fixed shape.

gases are those substance which have no fixed shape and volume.

On the basis of chemical properties matter is classified in three forms: elements, compound and mixtures

Elements : these are the substance in simplest naturally occurring form. These substance cannot be further split in more simpler form using any chemical method.

Elements can be further divided as metal, non-metal and metalloid.

Metal are the strong elements(have high tensile strength) that are good conductor of electricity. They are malleable, ductile and lustrous. They have high density and sonorous.

Non-metal are low tensile strength element that do not conduct electricity. They are brittle and have low melting and boiling point.

Metalloids are the elements that show some properties of metal and some properties of non-metal.

Compounds are substance made up of two or more elements chemically combined in a fixed ratio.

Mixture is a substance that is made up of two or more elements physically combined. mixtures are of two types: homogenous mixture and heterogenous mixtue

Homogenous mixture: this type of mixture have their components uniformly mixed with each other. The components cannot be distinguished.

Heterogeneous mixture: those mixture in which one substance remain separate and can be distinguished from the rest of components are heterogenous mixture.