SHAM ACADEMY

 Chemical Reactions and Equations Chemistry:-  The theoretical and experimental study of nature, composition, preparation, isolation and uses of matter is known as Chemistry. Chemical Reaction:-  Chemical reaction is the process by which two or more substances react with each other to form new substance with different properties. Only a rearrangement of atoms takes place in a chemical reaction. Example:    2H 2 + O 2  → 2H 2 O Here H 2 and O 2 take part in chemical reaction and produce a product of new property H 2 O Some more examples of chemical reactions: ➤Iron rod comes in contact of moisture and gets rusted. ➤Grapes get fermented ➤Food is cooked. ➤Food get digested in our body. ➤Respiration Determination of Chemical Reaction:- These are the following changes to determine that the chemical reaction has taken place: Change in state Change in colour Evolution of gas Change in temperature Formation of precipitate Characteristics of Chemical Reactions:- 1. Change in state:- The combu

Light - Reflection and Refraction Light:-  Light is a form of energy that enables us to see things around us.  Light starts from a source and bounces off from objects which are perceived by our eyes and our brain processes this signal, which eventually enables us to see. Some common phenomena:- There occur some common wonderful phenomena associated with light are image formation by mirrors, twinkling of stars, beautiful colors of rainbow, bending of light by a medium. Nature of Light:-  Light behaves as- ray  (e.g. reflection and refraction) wave  (e.g. interference and diffraction) particle  (e.g. photoelectric effect) Properties of Light:-  Light is an electromagnetic wave, so does not require any medium to travel. Light tends to travel in straight line. Light has dual nature i.e. wave as well as particle. Light casts shadow. Speed of light is maximum in vacuum. Its value is 3 × 10 8  m/s. When light falls on a surface, following may happens-   Reflection Refraction Absorption How do