NCERT Solutions for Class 9th Science
Chapter 2. Is Matter around us Pure
Que: - What is solution?
Ans: - A solution is a homogeneous mixture of two or more substances. Ex. – lemonade and soda water etc.
Que:- What is mixture ?
Ans:- A mixture is a combination of two or more substances which show the properties of each of the substance combined. A mixture of iron powder and sulphur show the properties of both sulphur and iron.
Que: - write the type of mixture? Difined them ?
- Homogenous mixture – Mixture having uniform composition are called homogeneous mixture.
- Heterogeneous mixture - – those mixture that do not have uniform composition are called heterogeneous mixture
Que: - Write the type of solution?
Ans: - There are three type :-
- Colloidal solution
- Concentration solution
Que: - What is suspension?
Ans: - suspension is a heterogeneous mixture which solids are dispersed in liquids are called suspension.
Que: - What is solute?
Ans: - The component of the solution that is dissolved in the solvent (usually present in lesser quantity) is called
Que: - Write the properties of a solution?
Ans: - Properties of a solution
- A solution is a homogeneous mixture.
- The particles of a solution are smaller than 1 nm.
- They cannot be seen by naked eyes.
- They do not scatter a beam of light passing through the solution.
- The path of light is not visible in a solution.
- The solute particles cannot be separated from the mixture by the process of filtration.
Que : - Write the properties of suspension.
Ans : - The properties of suspension.
- Suspension is a heterogeneous mixture.
- The particles of a suspension can be seen by the naked eye.
- The particles of a suspension scatter a beam of light passing through it and make its path visible.
- They can be separated from the mixture by the process of filtration.
Que:- Write the properties of a colloid ?
Ans: - The properties of a colloid
- A colloid is a heterogeneous mixture.
- The size of particles of a colloid is too small to be individually seen by naked eyes.
- Colloids are big enough to scatter a beam of light passing through it and make its path visible.
- They do not settle down when left undisturbed, that is, a colloid is quite stable.
Que : - What is solubility?
Ans; - The amount of the solute present in the saturated solution at this temperature is called its solubility.
Que: - Write the type of solution? Define them ?
- Saturated solution – When no more solute can be dissolved in a solution at a given temperature, it is called a saturated solution.
- Unsaturated solution – The amount of solute contained in a solution is less than the saturation level, it is called an unsaturated solution.
Que: - What is solvent ?
Ans;- The component of the solution that dissolves the other component in it (usually the component present in larger amount) is called the solvent.
Que: What is decantation?
Ans: The process of separating a solid from a liquid by pouring out the liquid is known as decantation.
Que:- What is dilute ?
Ans:- Depending upon the amount of solute present in a solution, it can be called a dilute.
Que: - How can we separate cream from milk?
Ans: - By the centrifugation.
Que; - What is chromatography?
Ans: - This process of separation of components of a mixture is known as chromatography.
Que: - What is chemical change ?
Ans:- Chemical change brings change in the chemical properties of matter and we get new substances. A chemical change is also called a chemical reaction.
Que:- How can we separate mixture of two imscible liquid?
Que:- How can we separate a mixture of salt and ammonium chcoride?
Ans:- By susblimation
Que:-What is crystallization?
Ans:- Crystallisation is a process that separates a pure solid in the form of its crystals from a solution.
Que:- Write the difference between a pure substance and a mixture?
Que:-What are the types of pure substance?
Ans; - There are two types :-
Que: What is element?
Ans: An element is a pure substances of matter. Which can’t be broken down into simpler substances by chemical method.
Ex. - copper, Iron, Alumunium, Oxygen, nitrogen etc.
Que: Write the types of element and define them ?
Ans: Element can be normally divided into metal non-metal and metalloids.
2. Non metal -
3. Metalloids:- some elements have intermediate properties between those of metals and non-metals they are called metalloids examples: are boron, silicon germanium etc.
Que: Write the properties of metal and non-metal?
Ans: Metals usually show some or all of the following properties:
• They have a lustre (shine).
• They have silvery-grey or golden-yellow colour.
• They conduct heat and electricity.
• They are ductile (can be drawn into wires).
• They are malleable (can be hammered into thin sheets).
• They are sonorous (make a ringingsound when hit).
Non-metals usually show some or all of the following properties:
• They display a variety of colours.
• They are poor conductors of heat and electricity.
• They are not lustrous, sonorous or malleable.
Que- What is compound?
Ans- A compound is a substance composed of two or more elements, chemically combined with one another in a fixed proportion.