Is Matter Around Us Pure Notes

Is Matter Around Us Pure Class 9th Notes

Matter can be mixed in different ways, this makes mixture. This mix of matter can include basic elements (the building blocks of everything) or compounds (where elements are joined together). We science students have techniques to separate mixtures into their pure components. In this chemistry notes we will learn, is matter around us pure for 9th class science students. 

Imagine sugar dissolving completely in water, creating a solution. The main part is the solvent (like water), and the smaller part is the solute (like sugar). Concentration measures how much solute is in the liquid.

When things do not dissolve and you can see them in the mix, it's called a suspension. 

Colloids are special mixtures where tiny particles are too small to see but can make light scatter. They're used in various scientific applications.

Pure substances can be elements (can't be broken down) or compounds (different elements combined). Compounds have their unique properties, different from their parts.

In a mixture, it behaves like the things in it, but compounds have their own distinct properties.

What is Mixture?

A mix which contains more than one form of pure matter is called as mixture. So, we can say that, when we mix different stuffs together then mixture get formed. It can be elements (like the building blocks of matter) or compounds (when elements are stuck together) mixed in any way.

Example of mixture: 

1. Soil is example of mixture.
2. Sodium Chloride (NaCl) in water is also an example of mixture. NaCl is pure substance and cannot be further separated by physical processes, but mixture of NaCl in water is separated by physical processes of evaporation. 
3. Other example of mixtures include air, concrete, beach sand, ocean water, paint etc.

Separating Mixtures

We can use special methods to separate mixtures into pure things. Evaporation is one of the physical process methods, which can be used to separate mixtures into pure substances. 

Other physical process method of separation of mixtures are filtration, distillation, decantation, magnetic separation, chromatography, centrifugation, crystallisation and sublimation. 

What is Solution?

Homogeneous mixture of two or more substances is called as solution. We can say that, mixing things like sugar and water so well, that you cannot see the sugar anymore. This perfect mixture is called as solution. The main part is called the "solvent," and the small part is the "solute".

Example of solution: 

1. SaltWater - when we dissolve salt in water then it makes solution. 
2. Sugar in tea - when we add sugar in tea, then sugar dissolve in tea and makes sugar solution with tea. 
3. Other examples of solutions include lemonade, soda, vinegar, mouthwash etc. 

Properties of Solution

• A solution is homogeneous mixture. i.e., solutions are uniform throughout means the composition is consistent at molecular level. We cannot differentiate between solute and solvent. 
• Particles of solution are very small, that is about 1nm (10^-9 metre) in diameter. These small particles are no seen by naked eyes. 
• Due to this very small particle size, solutions don't scatter the beam of light passing through the solution. Therefore, the path of the light, which is traveling through the solution is not visible .
• Solutions are stable means we cannot separate solute from solution by filtration process. Also, solute particle cannot settle down in bottom of the solution containing container, when left undisturbed for long time. 

Concentration of a Solution

Concentration is how much solute is present in solvent to make solution. Depending on the amount of solute in the solution, the solution can be dilute or concentrated solution. 

Dilute Solution

Dilute solution are the solutions in which amount of the solute is very less. So, we can say that dilute solutions have low concentration.

Concentrated Solution

Concentrated solutions are the solutions in which amount of the solute is very high. So, we can say that concentrated solutions have high concentration.

Saturated Solution

Saturated solutions are the solutions in which we cannot add solute anymore. That is, we come at a point where further adding of solute is not possible at given temperature. Type of solutions are known as saturated solutions. 

The amount of the solute present in the saturated solution at that temperature is known as its solubility. 

Unsaturated Solution

Solutions in which we can add solute easily and solution does not have at its saturation level. That type of solutions is known as unsaturated solutions. 

Formula of expressing concentration of solutions

• Mass by mass percentage of a solution formula.

        Mass by mass % of a solution = (Mass of solute / Mass of solution) x 100

• Mass by volume percentage of a solution formula.

        Mass by volume % of a solution = (Mass of solute / Volume of solution) x 100

• Volume by volume percentage of a solution formula.

        Volume by volume % of a solution = (Volume of solute / Volume of solution) x 100

What is Suspension?

When you mix things that cannot dissolve and you can see them in the mixture, that's called a suspension. Suspension is non-homogeneous mixture. 

We can also say that suspensions are heterogeneous mixtures, in which solute particles do not dissolve but remains suspended in bulk of the solution.  

Example of Suspension:

1. Muddy water formed when soil particles are mixed with water, this formation is example of suspension.
2. Medicinal syrup such as cough syrup, is the example of suspension.
3. Other examples of suspensions include orange juice with pulp, dust in air, river water, paint, lotions and creams. 

Properties of Suspension

• Suspension is the heterogeneous mixture.
• Suspension particles can be seen with naked eyes. 
• Suspension particles can easily scatter the beam of the light passing through suspension. Therefore, path of the light passing through the suspension is visible. 
• Solute particles of suspension settle down in bottom of the suspension containing container, when left undisturbed for long time. As a result, when all solute particles settle down, suspension breaks, and it do not scatter light anymore. 

What are Colloids?

Colloids are mixtures where the tiny particles are so small that you cannot see them, but they can make light bounce around. Colloids have property of scattering of lights. We can use them in many things, and the tiny particles are called the "dispersed phase." 

Size of particles in colloids is bigger than solution but smaller than that of suspension. Due to small size of particles, we cannot see particles in colloids. But these small particles can easily scatter the beam of light. This scattering of light is known as Tyndall effect. This Tyndall phenomenon is the characteristic property of colloids. 

Example of colloids:

1. Milk is the common example of colloids. Milk as colloid contains small fat droplets dispersed in water.
2. Fog is the natural colloid in the air.
3. Other example of colloids includes mayonnaise, whipped cream, shaving cream, smoke, emulsion etc. 

Properties of colloids

• Colloids are heterogeneous mixture. 
• Size of particles in colloid is too small to see individually with naked eyes. 
• However, particles in colloids are big enough to scatter the beam of light. Hence, colloids show Tyndall effect.
• Colloids are quite stable as they do not settle down when put undisturbed for some time.
• Particles of the colloids are not separated by simple filtration methods but can be separated by special methods like centrifugation.

Colloidal solution contains two parts, one is dispersed phase, and another is dispersing medium. Dispersed phase is the salute part, which is mixed with main part. This main part in which dispersed phase get mixed is known as dispersing medium.

Type of colloids

Colloids are classified as per the state (solid, liquid or gas) of dispersed face and dispersing medium.

Dispersed Phase	Dispersing Medium	Type of Colloid	Example of Colloid
Liquid	Gas	Aerosol	Fog, clouds, mist
Solid	Gas	Aerosol	Smoke, automobile exhaust
Gas	Liquid	Foam	Shaving cream
Liquid	Liquid	Emulsion	Milk, face cream
Solid	Liquid	Sol	Milk of magnesia, mud
Gas	Solid	Foam	Foam, rubber, sponge, pumice
Liquid	Solid	Gel	Jelly, cheese, butter
Solid	Solid	Solid Sol	Coloured gemstone, milky glass

Pure Substances

There are two kinds of substances. 

1. Elements: These are the basic building blocks of everything and can't be broken down.
2. Compounds: These are formed when different elements are stuck together in a certain way. Compounds have their own properties that are different from their parts.

What is element?

The term element was first introduced by the scientist Robert Boyle in 1661. Scientist Antoine Laurent Lavoisier define the element as the basic form of the matter, which cannot be subdivided into simplest forms by chemical reaction.  

Elements can be classified as metals, nonmetals and metalloids. 

Properties of Metals

Metals show some of the below properties or all of the below properties-

1. Metals have lustre and are shining.
2. Metals have silvery-grey or golden-yellow in colour.
3. Metals conduct heat and electricity. 
4. Metals are malleable and can be converted in thin sheets with the help of hammer.  
5. Metals are ductile and can be drawn into wires easily.  
6. Metals are sonorous and can produce ringing sound when hit. 

Example of Metals:

Example of metals are gold, silver, iron, copper, sodium, potassium etc.

Interesting fact about metals: Mercury is the only metal that is liquid at the room temperature. 

Properties of Non-Metals

Nonmetals show some of the below properties or all of the below properties-

1. Nonmetals shows different colours. 
2. Nonmetals are non-lustrous, means do not shine. 
3. Nonmetals are poor conductor of the heat and electricity. 
4. Nonmetals are not malleable and cannot be converted in thin sheets. 
5. Nonmetals are not ductile and cannot be drawn into wires easily.  
6. Nonmetals are not sonorous and cannot produce ringing sound when we hit them. 

Example of Nonmetals

Example of nonmetals are hydrogen, carbon, oxygen, nitrogen, iodine, bromine, chlorine etc.

Properties of Metalloids

Properties of metalloids are intermediate, means that shows properties of metals and nonmetals. Metalloids shows mixed properties. 

Example of Metalloids

Example of metalloids are silicon, boron, germanium etc.

Difference between mixture and compound

Mixture	Compound
Elements or compounds just mix together to form a mixture and no new compound is formed.	Elements react to form new compounds.
A mixture has a variable composition.	The composition of each new substance is always fixed.
A mixture shows the properties of the constituent substances.	The new substance has totally different properties.
The constituents can be separated fairly easily by physical methods.	The constituents can be separated only by chemical or electrochemical reactions.

Properties

When you have a mixture, it behaves like the things in it. But when you have a compound, it has different properties than its parts.

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