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The chapter Is Matter Around Us Pure? Class 9 Science is devoted to the concept of purity in substances, how pure and impure substances are different, and the different techniques to separate a mixture. Mastering the important points of this chapter is necessary for students to face their examinations and apply these concepts in everyday life. Below are some important questions from the Class 9 Is Matter Around Us Pure chapter and explanations that will clarify the essential points of this chapter:
PREMIUM EDUCART QUESTIONS
(Most Important Questions of this Chapter from our 📕)
We have added the links to Chapter 2 Science Class 9 Most Important Questions PDFs, in the table given below. You can download them without having to share any login info.
Matter is anything that has mass and occupies space. It is everything we can see, touch, or smell. There are three primary states of matter: solid, liquid, and gas.
Matter is made up of atoms and molecules, and its purity/impurity depends on the order in which its particles are present.
Pure matter is that in which all the molecules are of only one kind: either atoms only (in pure elements) or molecules only (in pure compounds). Pure matter possesses uniform properties throughout and contains no impurities, and it is also homogeneous at the level of molecules.
Examples of Pure Matter:
Molecules: These are pure substances that consist only of one type of atom. Examples are: Gold (Au): It is made of only gold atoms. Oxygen (O₂): It is made of only oxygen molecules. Carbon (C): It is made of carbon atoms.
Compounds: This is a pure substance formed from two or more different types of atoms that bond together in fixed ratios. Examples are:
Water (H₂O): It consists of two hydrogen atoms and one oxygen atom.
Sodium Chloride (NaCl): It consists of sodium and chlorine atoms in a 1:1 ratio.
Carbon Dioxide (CO₂): It consists of one carbon atom and two oxygen atoms.
In other words, both elements and compounds are pure matter since they consist of only one type of atom or molecule.
A mixture is a physical mixture of two or more substances not chemically bonded. The different components of a mixture retain their individual properties and can be separated using physical methods. Mixtures may be classified into either heterogeneous or homogeneous.
Homogeneous Mixtures (Solutions):
These mixtures have components evenly distributed, meaning it is impossible to distinguish one part from the other.
Example: Sea water, air, and alloys such as brass are homogeneous mixtures.
Heterogeneous Mixtures:
In such a mixture, the constituent particles are not evenly distributed; thus, separate components can easily be distinguished.
Example: Sand-water mixture, salad, or trail mix are heterogeneous mixtures.
Most matter in nature is not pure. For instance, the air we breathe, the water we drink, and even the food we eat are all made up of mixtures of different elements, a few of them impurities. Impurities are unwanted substances that mix with the main substance.
For instance:
Pure substances are relatively rare in nature. The majority of materials we experience in our everyday life are mixtures, and this means that the matter around us is primarily impure.
Purity is required in most elements of life, particularly science, health, and industries. Here is the main argument for why purity counts.
In Scientific Experiments:
For scientists, conducting experiments in which only pure elements are involved is imperative since impurities may give off different results that may mislead people. For instance, when testing on properties of a certain chemical compound, impurities may break down the reaction in the process that is taking place; thus the yielded results are wrong.
In Drugs:
The potency of drugs and their safety is comprehensively attributed to the impurity in drugs. A drug with impurities may not work as expected or may cause unwanted side effects. In the pharmaceutical industry, purity is vital, as even small quantities of contaminants can make a medication hazardous.
In Industry
Most industrial processes require high purity for efficient function. A high-purity form of silicon, for instance, is used to produce computer chips. Impurities could result in waste products or products that don't work. Production costs rise since more is wasted during the manufacturing process.
In Food and Water:
Food and water also require purity. Contaminated food and water can pose serious health issues. Food processing companies and water purification plants take strict measures to ensure that their products are pure and free from harmful chemicals.
There are several methods used to separate mixed compounds and purify substances in laboratory and industrial settings. Some common examples are given below:
Filtration:
Filtration is the method by which solid impurities are separated from a liquid or gas. For instance, when you drink water, it passes through a filter in which all impurities, such as dirt and germs, are removed.
Distillation:
Distillation is a technique used to fractionate liquids based on their boiling point. It is mainly applied for purifying liquids. For example, by distillation, water can be separated from the impurities or other liquids by heating the mixture such that the water gets evaporated and then again condenses into a liquid form.
Chromatography:
Chromatography is a procedure for separating various constituents of a compound. It can be widely seen in laboratories to accomplish chemical analyses. For example, it can isolate pigments present in plants, drugs from samples of blood, etc.
Crystallisation:
It is the formation of solid crystals from a uniform solution. This method can be used to purify any salt or something else.
Magnetic Separation:
In some mixtures, one of the constituents might be magnetic and therefore can be separated from the others by use of a magnet. This is very commonly done by separating iron filings from a mixture of sand and iron.
Based on the quantity of solute dissolved in a given amount of solvent, solutions can be categorised as follows:
a) Saturated Solution:
This is a solution that contains the maximum amount of solute possible at a certain temperature.
Example: Saltwater with no additional addition of salt to be dissolved.
b) Unsaturated Solution:
This is a solution that can be dissolved into additional amounts of the solute.
Example: Water with some salt dissolved but has space for more.
c) Supersaturated Solution:
At a certain temperature, this solution contains more solute than what could usually dissolve.
Example: A very hot sugar solution in water cools down but does retain excess sugar.
A colloid is a mixture in which one substance is evenly distributed within another; the particles will remain suspended, rather than settling. Such mixtures include particles that are too small to be observed without a microscope and yet, through their dimensions, can scatter light.
For example: milk, fog, paint, butter.
The Tyndall effect is defined as the scattering of light, which occurs when light travels through a colloidal mixture. It is visible if light passes through a colloid in such a manner that the path of the light can be seen as the light scatters off the present particles.
Example: The way light scatters in a room covered by fog.
Air is considered a mixture since it comprises several gases. These gases are nitrogen, oxygen, and carbon dioxide, among several others, in their respective amounts. Gases possess individual properties and may be separated through the physical separation of liquefaction or distillation.
Understanding matter and how we classify it as pure substances, mixtures, and colloids is the simplest way to understand the world. This chapter, therefore, emphasises how we classify matter in terms of composition, along with the ways through which we separate mixtures into their parts. Being able to work with mixtures, through processes like filtration, distillation, and chromatography, whether in the lab or in our daily lives, is of prime importance to various applications both in science and industry.
You must learn the general ideas of purity, mixtures, and separation methods. Is Matter Around Us Pure? Important Questions will give you deeper insight into the material and train you to better deal with the examination questions.
We hope that you practice the above Class 9 Science Chapter 2 Extra Questions and achieve your dream marks.
All the Best!
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