EDUCATRIX

 Atoms are the building blocks of all the matters around us. Like bricks used for building a huge building. Size of atoms Atoms are very very small, can’t see with our naked eyes. They are smaller than anything that we can imagine. For example, A small sheet of paper is made up of millions of atoms.  Since atoms are too small, atomic radius is measured in nanometres.  1nanometre = 1/10 ⁹ meters  or 1m = 10⁹nm  Symbols of atoms of different elements  There are 118 elements identified and named officially by IUPAC. IUPAC stands for international union of pure and applied chemistry, it is the international scientific organisation which approves the name of elements, symbols and units.  Each atoms of element are provided with specific symbols to identify then and we use this symbols to represent chemical reactions.Dalton was the first scientist to use symbols for elements to represent them. But present symbols provided by IUPAC is different from that used ...

 House hold electric circuit The pictorial representation of household electric circuit is given in the below diagram. Tree system  Generally, for the household connection two lines are taken from the distribution system as shown in the diagram. Starting from the left hand side of the diagram, one red and one black line connection is provided to a house, red line represent live line or phase line and the black line represent neutral line. Initially they are connected to watt hour meter which is used to measure the current used in that particular house for billing purposes. From there earthing should be done, which is shown in the diagram in green colour. Colour code of household electric wires and potentials difference between them As we mentioned above there are three lines in household electrical circuit-  live line(phase line), neutral and earth line. For live which is also known as phase line we have to use red coloured wire. For neutral line, black wire is used. And ...

 In general, energy can be defined as the capacity to do works or energy can be considered as the force that makes the things move . Energy is a fundamental part of life and it comes in different forms. Everything occurs around as is associated with some form of energy. Types of energy  Heat energy - energy from the heat Light energy - energy from the light Muscular energy - energy from the food we eat Wind energy - energy due to the movement of air Chemical energy - energy produced due to chemical reactions  Mechanical energy - energy due to the movement of machinery  Electrical energy - energy associated with movement of electric charges  Nuclear energy - energy stored in atoms  Energy is present all around universe. In coming topics we study in details about different energy forms there transfer, source, uses etc.. Law of conservation of energy  According to the law of conservation of energy, energy can neither be created nor be destroyed, it can tr...

  Matter around as is made up of particles. If we go on dividing the matter we shall get smaller and smaller particles. Ultimately a stage will come across the smallest particles beyond which further division will not be possible. British chemist John Dalton provided the basic theory about the nature of matter, which explains idea of divisibility of matter. And he took the name of the smallest particles of matter as atom. According to Dalton's atomic theory all the matters is composed of small particles called atoms and he suggested postulates of his theory as below All the matter is made up of tiny particles called atoms, which participate in chemical reactions. Atoms are individual particles, which cannot be created or destroyed during a chemical reaction. Atoms of a given element is identical in mass and chemical properties. Atoms of different elements have different mass and chemical properties. Atoms combine in ratio of whole numbers to form compounds. The relative number and ...

  Most of the substances found in nature are mixtures soil, air, sand etc. For some useful purposes separation of mixture is done in our daily life. There are different scientific methods to separate mixtures into it components. The choice of the methods of separation of components depends on the properties of the components of a mixture. Different types of separation methods are, Distillation  Fractional distillation  Separation using separating funnel  Sublimation  Centrifugation Chromatography 

 Law of reflection for a plane mirror is also applicable for spherical mirrors  Incident ray, reflected ray and normal at the point of incident are in a same plane. Angle of incidence and angle of reflection are equal in spherical mirrors  Rules of drawing ray diagram for spherical mirrors  Ray of light passing parallel to the principal axis  For concave mirror Ray of light parallel to the principle axis converges and passes through the focus of the mirror. For convex mirror Ray of light parallel to principal axis diverges from the focus of the mirror. Ray of light passing through the focus of the mirror  For concave mirror Ray of light passing through the focus of mirror reflects and passes parallel to the principal axis. For convex mirror Ray of light passing through the focus of mirror reflects and passes parallel to the principal axis. Ray of light incident obliquely at the poles For both concave and convex mirrors the light ray incident obliquely at th...

 Antoine Lavoisier laid the foundation of chemical science by establishing two laws of chemical combination. ( Joseph L Proust was also a part of the experimentation that led for formulation of this laws). There are two laws of chemical combination law of conservation of mass ans law of constant proportions  Law of conservation of mass Law of conservation of mass states that mass can neither be created more be destroyed in a chemical reaction. Law of constant proportions  The law of constant proportions states that, in a chemical substance the elements are always present in a definite proportions by mass.

 When light enters from one medium to the another with different optical density, the direction of light ray changes at the point of intersection between two mediums due to refraction  When light ray enters from a denser medium to a rarer medium it bend away from the normal (as shown in figure 1). As the angle of incidence increases the refracted ray moves further away from normal.  At a particular angle of incidence, the refracted ray passes through the plane of intersection between two medium, this angle of incidence is known as critical angle (as shown in figure 2).  If the angle of incidence is greater then the critical angle, refraction doesn’t occurs and all the light rays will be reflected back to the same medium. This is known as total internal reflection 

  Ant sting contain formic acid when ants bits formic acid is injected to our body which causes inflammation, irritation and itching on skin. Since acid can be neutralised by base, so remedy for ant bites is rub the affected part with basic substances like  baking soda, calamine lotion etc so the formic acid in our skin get neutralised.

 When a ray of light pass through a colloidal fluid or suspension , the tiny particles get illuminated due to scattering. Because of this the path of the light made visible. This phenomenon is know as tyndal effect. The intensity of the scattering depends up on the size of the particles in the medium through light passes. As the size increases the intensity of the scattering also increases.   In a misty morning the path of light is visible through the areas with dense trees, because mist is a colloid of air and water vapour. Particles in the mist is big enough to scatter the sunlight so the path of the light is visible.

 There are two laws of chemical composition  Law of conservation of mass Law of constant proportions  Law of conservation of mass Law of conservation of mass state that mass can neither be created nor destroyed in a chemical reaction. Example:- 2grams of hydrogen react with 16grams of oxygen to produce 18grams of water. The total mass in the reactant and total mass in the product is same. Law of constant proportions Law of constant proportions state that in a chemical substance the elements are always present in a definite proportion by mass. Example:- in water the ratio of mass of hydrogen to the mass of oxygen is always 1:8. That means 1grams of hydrogen need 8grams of oxygen to react together and form 9gm of water.