Chemistry
What are things?
Things are made up of materials.
What are Materials?
· Materials are used to make different type of things
Ex: a) Steel is material used to knives, car, utensils
b) Wood is used to make furniture:
c) Paper is material used to make books
· Same things made from different kind of material
Ex: Furniture made from wood, Plates made from plastic, ceramic and glass.
List few characteristics of Mass?
· All materials occupy Space.
· The amount of space occupied by something is called as Volume
· All materials have Mass
· Amount of matter in an object is known its mass
· Mass is measured using balance
· All Materials have mass and space.
· Anything that occupies Space and has mass is called as Matter.
· All the substances in the universe are made up of matter
Write about atom?
· John Dalton proposed the concept of atom
· Water is made up of two different kind of atom Such as Hydrogen, oxygen.
· one molecule of water has two atom of hydrogen and one atom of oxygen.
Define Molecule?
· When two atom bound together by bonds it is called as molecule.
· Smallest particle of a compound is a molecule.
· These are 118 different elements
· 92 elements are occurs naturally.
· Ex: for common elements are Hydrogen, Oxygen, Zinc, Helium, Sodium, Silver, carbon, Gold, Sulphur.
Define Element?
· when a substance is made by same type of atom is called Element
· Ex: Iron, Gold, Hydrogen, Oxygen
Define Compound?
When a substance is made up of two or more elements it is called as compounds.
· Ex: Water, Salt (Nacl)
· Sugar is made C₂ H₂,0₂
· Sand is made from silicon, oxygen
What is Classification?
· Classification is grouping things together with similar properties.
· Materials are classified based on their appearance, lustre, Texture.
How are materials classified based on appearance?
· Based on Appearance materials are classified into lustrous and non lustrous.
· Lustrous are shiny materials eg. Silk cloth, metal spoon
· Non lustrous are non shiny materials eg. Iron, rod, paper, wood.
How are materials classified based on texture?
· Based on texture materials are classified as rough and smooth.
· Rough surface materials having bumps & ridges or irregularity on their Surface.
· Ex: Sand paper, rock, tyre
· Smooth surface materials are even & regular.
Ex: Marbles, Tiles, Granite.
How are materials classified based on hardness?
· Based on hardness, materials are classified into hard and soft.
· Hard materials cannot be easily compressed. Eg: Iron and glass
· Materials that can be easily compressed, cut, bent or scratched
· Ex: Sponge, cotton.
What are the three states of matter?
There are the states of matter. Solid, liquid, gas.
List the various Properties of Solid?
a) Solids do not easily change their shape.
b) Solid have rigid fixed shape and fixed volume.
c) Solids, molecules are tightly packed and they attract each other very strongly.
d) Solid molecules are in compressible, do not move
e) They exert very little energy.
List the various Properties of liquid ?
a) Liquid change Shape but not volume.
b) Liquid, molecules are loosely packed
c) They are in compressible.
d) Molecules slide over each other.
e) They exert more kinetic energy.
List the Properties of Gas?
a) In Gas molecules are loosely packed.
b) They have no definite shape or volume
c) Molecules can be compressible.
d) Molecules move quickly & freely.
e) They exert lot of Kinetic energy much more than liquids.
Define Plasma?
· Fourth State of matter is plasma
· Plasma are gases that are heated so high that this electrons to be removed easily.
· Sun is made up of plasma that is made up of Hydrogen & Helium fluorescent lamps, lightening, Auroras
What is the fifth state of matter?
· Fifth state of matter proposed now is Bose-Einstein condensate
· Starts when all atoms get cold, they begin to clump and become big blob that all look same.
What is Viscous liquid?
Some liquid flow very slowly, they are called as viscous liquid Ex: Honey, tar.
Solids, substances such as salt, sugar, chalk mix with water.
What is Miscible liquid?
Liquids which mix with each other are called as miscible liquids. Ex: coconut milk, milk, lemon juice.
What is Immiscible liquid?
· Liquids that do not mix with each other are called as immiscible liquids. Exc. coconut oil, kerosene, petrol.
· Oxygen, carbon dioxide is slightly soluble in water.
· Nitrogen is not soluble in water.
· Plants use carbon dioxide dissolved in water for photosynthesis.
· Fish use dissolved oxygen in water for breathing.
Define Density?
· Mass per unit volume of a substance is known as density.
· Substance which is denser (heavy) than water will sink Ex: Iron, aluminium.
· Substance which is less dense (lighter) than water was float Ex: Wood, Cotton
How are Matter classified?
Matter are classified based on their transparency as Transparent, Translucent, opaque.
Substances / materials that allow light to completely pass through them, it is Transparent. Ex: Water, air
Materials that allow partially light to pass thorough them, they are Translucent
Ex: Butter paper, frosted glass
Materials that do not allow light them are as opaque. Ex: Wood, plastic
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