Is Matter Around Us Pure
Frequently Asked Questions
A pure substance consists of only one kind of particles with a fixed composition throughout.
Impurities are unwanted substances mixed with a pure substance that alter its composition and properties.
Elements and compounds are the two categories of pure substances.
An element is a substance made up of only one type of atom, for example, hydrogen or oxygen.
A compound is a pure substance formed by the chemical combination of two or more elements in fixed proportions.
Water (H2O) is a compound made from hydrogen and oxygen.
A mixture is a combination of two or more substances physically mixed but not chemically combined.
Mixtures are of two types: homogeneous and heterogeneous.
A homogeneous mixture has uniform composition and appearance throughout, like salt dissolved in water.
A heterogeneous mixture has visibly different components and non-uniform distribution, like sand in water.
Sugar solution and air are homogeneous mixtures.
Oil and water, and soil are heterogeneous mixtures.
A solution is a homogeneous mixture of two or more substances, including a solute and solvent.
The substance present in smaller amount that dissolves in a solvent is called a solute.
The substance in which the solute dissolves to form a solution is called the solvent.
Salt dissolved in water is a solution.
It is the amount of solute present in a given amount of solvent or solution.
A saturated solution contains maximum amount of solute that can dissolve at a given temperature.
A solution that can still dissolve more solute at the same temperature is unsaturated.
Solubility is the maximum amount of solute that can dissolve in 100 g of solvent at a given temperature.
A suspension is a heterogeneous mixture where solid particles settle when left undisturbed.
Muddy water and sand in water are examples of suspensions.
A colloid is a heterogeneous mixture where particles are evenly spread and do not settle down.
Milk, fog, and butter are examples of colloids.
The dispersed phase and dispersion medium are the two components of a colloid.
The Tyndall effect is the scattering of light by colloidal particles in a mixture.
It is observed in colloids but not in true solutions.
The particle size ranges between 1 nm and 1000 nm in colloids.
Mixtures can be separated based on physical properties like particle size, solubility, and density.
Filtration separates insoluble solids from liquids using filter paper.
Evaporation separates volatile substances like water from non-volatile solutes like salt.
Distillation separates two miscible liquids based on their boiling points.
It separates a mixture of two or more liquids with close boiling points.
Sublimation separates solids that directly change into vapour on heating, such as camphor.
Crystallization purifies solids by forming pure crystals from their saturated solutions.
Chromatography separates colored mixtures based on solubility differences in a solvent.
It is used to separate pigments from plant extracts or ink.
Centrifugation separates heavier and lighter components by spinning rapidly.
Decantation is the process of separating liquids from solids by pouring out the clear liquid.
Sedimentation allows heavier particles to settle at the bottom due to gravity.
Mixtures can be separated physically, while compounds require chemical methods to separate.
Elements consist of one type of atom; compounds are formed by chemical bond between elements.
Evaporation method is used to obtain common salt from sea water.
The clear liquid collected after distillation is called the distillate.
Alloy is a homogeneous mixture of two or more metals or a metal and non-metal, like bronze.
Brass (copper + zinc) and steel (iron + carbon) are common examples of alloys.
Air is a homogeneous mixture of various gases like nitrogen, oxygen, and carbon dioxide.
Liquids that do not mix uniformly, like oil and water, are immiscible liquids.
Immiscible liquids can be separated by using a separating funnel.
Matter around us may be pure or impure; understanding mixtures and separation methods helps in obtaining pure substances.
