This document defines key chemistry concepts including pure substances, elements, compounds, mixtures, solutions, suspensions, colloids, evaporation, distillation, filtration, physical properties, physical changes, chemical changes, flammability, and reactivity. Pure substances such as sugar and salt have the same composition. Elements like carbon cannot be broken down further, while compounds like water are made of two or more simpler substances. Mixtures vary in homogeneity from solutions to suspensions to colloids. Physical changes alter properties but not substances, while chemical changes form new substances.
Separation of substances class 9 - khushali thackerSourabh Soni
IS THE MATTER PURE AROUND US ?
When two or more elements and compounds mix together,
and do not interact chemically, then the resulting substance is
known as a mixture.
Separation of substances class 9 - khushali thackerSourabh Soni
IS THE MATTER PURE AROUND US ?
When two or more elements and compounds mix together,
and do not interact chemically, then the resulting substance is
known as a mixture.
The important methods for separation and purification of organic compounds are: Crystallization, Sublimation, Distillation, Differential extraction and chromatography.
1. Pure Substances
Definition: Matter that always has the same
composition. Substances can be classified into two
categories- elements and compounds.
Examples: sugar, salt, etc...
3. Compounds
Definition: A substance that is made from 2 or
more simpler substances and can be broken down
into those simpler substances.
Examples: H2o (water), NaCl (salt)
7. Colloids
Definition: Contain some particles that are
intermediate in size between the small particles in a
solution and larger particles in a suspension.
Examples: fog, milk
8. Evaporation
Definition: The process that changes a substance from a
liquid to a gas or the opposite by reaching boiling point or
melting point.
Examples: Water, Ice,
9. Distillation
Definition: A process that separates substances in a
solution based on their boiling points.
Examples: Fresh water for submarines
10. Filtration
Definition: A process that separates materials
based on their particle size.
Examples: Tea bag, Spaghetti strainer.
11. Physical Properties
Odor- What something smells like
Melting/Freezing Point- The temperature at which a solid changes to a liquid or the opposite.
Boiling Point- The temperature at which a liquid turns into a gas.
Solubility-The ability of a substance to dissolve another.
Density- D= M/V
Viscosity-Resistance to flow.
12. Physical Change
Definition: Occurs when some of the properties of a
material change, but the substances in the material
stay the same.
Examples: haircut, melting butter,
14. Reactivity
Definition:The property that describes the how readily a
substance combines chemically with other substances.
Examples: Pure Potassium and water, oxygen and iron.
15. Chemical Change
Definition: Occurs when a substance reacts and forms
one or more new substances.
Example: Bleach and jeans, rotting fruit(color), bubbles,
production of gas, change in color, formation of
precipitate.
16. What kind of change is
happening when paper
burns?