{"id":4960,"date":"2023-03-14T13:16:20","date_gmt":"2023-03-14T13:16:20","guid":{"rendered":"https:\/\/theexampillar.com\/ncert\/?p=4960"},"modified":"2023-03-28T06:12:57","modified_gmt":"2023-03-28T06:12:57","slug":"ncert-solutions-class-9-science-chapter-2-is-matter-around-us-pure","status":"publish","type":"post","link":"https:\/\/theexampillar.com\/ncert\/ncert-solutions-class-9-science-chapter-2-is-matter-around-us-pure\/","title":{"rendered":"NCERT Solutions Class 9 Science Chapter 2 Is Matter around Us Pure"},"content":{"rendered":"

NCERT Solutions Class 9 Science\u00a0<\/span><\/h2>\n

The NCERT Solutions in English Language for Class 9 Science Chapter – 2 (Is Matter around Us Pure) <\/strong>has been provided here to help the students in solving the questions from this exercise.<\/span><\/p>\n

Chapter – 2 (Is Matter around Us Pure)<\/span><\/h2>\n

Question<\/strong><\/span><\/p>\n

1. What is meant by a substance?
\n<\/strong>Answer –\u00a0<\/strong>It is a pure single form of matter. A substance has definite properties and compositions. Example – Iron<\/span><\/p>\n

2. List the points of difference between homogeneous and heterogeneous mixtures.
\n<\/strong>Answer –<\/strong><\/span><\/p>\n

\n\n\n\n\n\n\n
Homogeneous mixture<\/strong><\/span><\/td>\nHeterogeneous mixture<\/strong><\/span><\/td>\n<\/tr>\n
Particles are uniformly distributed throughout the mixture<\/span><\/td>\nAll the particles are completely mixed and can be distinguished with the bare eyes or under a microscope<\/span><\/td>\n<\/tr>\n
Has a uniform composition<\/span><\/td>\nIrregular composition<\/span><\/td>\n<\/tr>\n
No apparent boundaries of division<\/span><\/td>\nNoticeable boundaries of division<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Question<\/span><\/strong><\/span><\/p>\n

1. Differentiate between homogenous and heterogeneous mixtures with examples.
\n<\/strong>Answer – <\/strong>The following are the differences between heterogeneous and homogenous mixtures.<\/span><\/p>\n

\n\n\n\n\n\n\n\n
Heterogeneous mixture<\/strong><\/span><\/td>\nHomogeneous mixture<\/strong><\/span><\/td>\n<\/tr>\n
All the particles are completely mixed and can be distinguished with the bare eyes or under a microscope<\/span><\/td>\nParticles are uniformly distributed throughout the mixture<\/span><\/td>\n<\/tr>\n
Irregular composition<\/span><\/td>\nHas a uniform composition<\/span><\/td>\n<\/tr>\n
Noticeable boundaries of division<\/span><\/td>\nNo apparent boundaries of division<\/span><\/td>\n<\/tr>\n
Examples: Seawater, blood, etc.<\/span><\/td>\nExamples: Rainwater, vinegar, etc.<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

2. How are sol, solution and suspension different from each other?
\n<\/strong>Answer –<\/strong><\/span><\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Attributes<\/span><\/th>\nSol<\/span><\/th>\nSolution<\/span><\/th>\nSuspension<\/span><\/th>\n<\/tr>\n<\/thead>\n
Type of Mixture<\/span><\/td>\nHeterogeneous<\/span><\/td>\nHomogeneous<\/span><\/td>\nHeterogeneous<\/span><\/td>\n<\/tr>\n
Size of particles<\/span><\/td>\n10-7<\/sup> \u2013 10-5 <\/sup>cm<\/span><\/td>\nLess than 1 nm<\/span><\/td>\nMore than 100 nm<\/span><\/td>\n<\/tr>\n
Tyndall effect<\/span><\/td>\nExhibited<\/span><\/td>\nNot exhibited<\/span><\/td>\nMay or may not be exhibited<\/span><\/td>\n<\/tr>\n
Appearance<\/span><\/td>\nUsually glassy and clear<\/span><\/td>\nUnclouded and clear<\/span><\/td>\nCloudy and opaque<\/span><\/td>\n<\/tr>\n
Visibility<\/span><\/td>\nVisible with an ultra microscope<\/span><\/td>\nNot visible<\/span><\/td>\nVisible with naked eye<\/span><\/td>\n<\/tr>\n
Diffusion<\/span><\/td>\nDiffuses very slowly<\/span><\/td>\nDiffuses rapidly<\/span><\/td>\nDo not diffuse<\/span><\/td>\n<\/tr>\n
Stability<\/span><\/td>\nPretty stable<\/span><\/td>\nHighly stable<\/span><\/td>\nunstable<\/span><\/td>\n<\/tr>\n
Settling<\/span><\/td>\nGet settled in centrifugation<\/span><\/td>\nDo not settle<\/span><\/td>\nSettle on their own<\/span><\/td>\n<\/tr>\n
Example<\/span><\/td>\nMilk, blood, smoke<\/span><\/td>\nSalt solution, Sugar solution<\/span><\/td>\nSand in water, dusty air<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

3. To make a saturated solution, 36g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature.<\/strong>
\nAnswer –
\n<\/strong>Mass of solute (NaCl) = 36 g
\nMass of solvent (H2<\/sub>O) = 100 g
\nMass of solution (NaCl + H2<\/sub>O) = 136 g
\nConcentration = Mass of solute\/Mass of solution x 100
\nConcentration = \"\\frac{36}{136}\\times = 26.47%
\nHence, the concentration of the solution is 26.47%<\/span><\/p>\n

Question<\/span><\/strong><\/span><\/p>\n

1. How will you separate a mixture containing kerosene and petrol (the difference in their boiling points is more than 25\u00b0C), which are miscible with each other?
\n<\/strong>Answer – <\/strong>The mixture of two miscible liquids such as kerosene and petrol whose boiling points differ by more than 25\u00b0C can be easily separated by the technique of simple distillation.<\/span>
\n\"NCERT<\/span><\/p>\n

The separation is based upon the principle that the boiling point of more volatile (low building liquid of the mixture. The vapour almost exclusively consists of the more volatile liquid Likewise at the boiling of the less volatile (high boiling) liquid, vapours almost entirely consists \u00a0of the less volatile liquid since the more volatile liquid has already distilled over. \u00a0 \u00a0\u00a0\u00a0<\/span><\/p>\n

2. Name the techniques used to separate the following:
\n<\/strong>(i) Butter from curd
\n<\/strong>(ii) Salt from seawater
\n<\/strong>(iii) Camphor from salt
\n<\/strong>Answer –<\/strong><\/span><\/p>\n

(i)<\/strong> Butter from curd can be separated by the technique of centrifugation.<\/span><\/p>\n

(ii)<\/strong> Salt from sea water can be separated by the technique of crystallization or by the evaporation.<\/span><\/p>\n

(iii)<\/strong> Camphor is sublimable but salt is not. So, camphor can be separated from salt sublimation technique.<\/span><\/p>\n

3. What types of mixtures are separated by the technique of crystallisation?
\n<\/strong>Answer – <\/strong>Homogeneous mixtures such as common salt solution and copper sulphate solution separated by technique of crystallization.\u00a0<\/span><\/p>\n

Question<\/span><\/strong><\/span><\/p>\n

1. Classify the following as physical or chemical changes:<\/strong><\/span><\/p>\n