tag:blogger.com,1999:blog-43938948247976620452024-03-09T00:37:01.610+05:30CBSE MASTER | NCERT Textbooks Exercises SolutionsCBSE Class 6th, 7th, 8th, 9th, & 10th | Help Guide | Solved Exercises | MCQs | Questions & Answers | Sample PapersUnknownnoreply@blogger.comBlogger311125tag:blogger.com,1999:blog-4393894824797662045.post-47825027367005721712023-02-22T07:49:00.007+05:302023-02-22T07:53:46.773+05:30Laser Sound and Light show at Rose Festival 2023 Chandigarh
This year, 3 days long, 51st Rose Festival 2023 was held from 17th February to 19th February at Rose Garden Chandigarh.
This year, the sound and light show, has been the main attraction of the Rose Festival 2023.
This Half an Hour long, scintillating and dazzling show of light and sound, revolving around theme of Azadi Ka Amrit Mahotsav and showcase the journey of The City Beautiful Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-6378113488689836132018-01-05T16:17:00.001+05:302018-01-05T16:17:10.734+05:30What produces more severe burns, boiling water or steam?
Answer : Steam produces more severe burns as compare to boiling water as it has extra high heat energy.
This is an answered question from Chapter 1. MATTER IN OUR SURROUNDINGS of CBSE Class 9th Science
Check for Complete
Exercise Solution for Chapter 1. MATTER IN OUR SURROUNDINGS | CBSE Class 9th Science
Unknownnoreply@blogger.com2tag:blogger.com,1999:blog-4393894824797662045.post-3573903159528212972018-01-05T16:16:00.002+05:302018-01-05T16:16:09.671+05:30Why is ice at 273 K more effective in cooling than water at the same temperature?
Answer : The heat energy absorbed by ice to change to liquid state, without showing any rise in temperature is known as the latent heat. We already know, the heat can change the physical state of a matter by overcoming the forces of attraction between the particles. For water freezing point and melting point is 0°C. So water has extra amount of hidden energy as compare to Unknownnoreply@blogger.com1tag:blogger.com,1999:blog-4393894824797662045.post-88924804087011723862018-01-05T16:15:00.002+05:302018-01-05T16:15:15.424+05:30Give two reasons to justify Question 6 from Chapter 1. MATTER IN OUR SURROUNDINGS
(a) water at room temperature is a liquid.
(b) an iron almirah is a solid at room temperature.
Answer : (a) water at room temperature is a liquid because its melting temperature is with in range of room temperature. As we know force of molecular attraction of a substance becomes high at low temperature and weak at high temperature. Due to this water at 0°C becomes solid Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-21219523782986030332018-01-05T16:13:00.004+05:302018-01-05T16:13:32.902+05:30What is the physical state of water at. (a) 25°C (b) 0°C (c) 100°C ?
Answer : Physical states of water at given temperatures :
(a) 25°C - Liquid as familiar water
(b) 0°C - Solid as ice
(c) 100°C- Gaseous as water vaporour
This is an answered question from Chapter 1. MATTER IN OUR SURROUNDINGS of CBSE Class 9th Science
Check for Complete
Exercise Solution for Chapter 1. MATTER IN OUR SURROUNDINGS | CBSE Class 9th Science
Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-30359098917843178272018-01-05T16:12:00.002+05:302018-01-05T16:12:19.532+05:30Arrange the following substances in increasing order of forces of attraction between the particles. water, sugar, oxygen.
Answer : Substances in increasing order of forces of attraction between the particles.
Oxygen
Water
Sugar
This is an answered question from Chapter 1. MATTER IN OUR SURROUNDINGS of CBSE Class 9th Science
Check for Complete
Exercise Solution for Chapter 1. MATTER IN OUR SURROUNDINGS | CBSE Class 9th Science
Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-57529068583766927002018-01-05T16:11:00.001+05:302018-01-05T16:11:20.858+05:30Give reason for the following observations Question3 from Chapter 1. MATTER IN OUR SURROUNDINGS
(a) Naphthalene balls disappear with time without leaving any solid.
(b) We can get the smell of perfume sitting several metres away.
Answer : (a) Naphthalene balls disappear with time without leaving any solid. This is due to the property of sublimation. Some solids do not exist in their liquid form or changes from solid to liquid; instead they directly evaporate from their solid form to Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-55056732356385573642018-01-05T16:08:00.003+05:302018-01-05T16:08:58.441+05:30Convert the following temperatures to the Kelvin scale. (a) 25°C (b) 373°C
Answer : Kelvin is the SI unit of temperature, 0° C =273.16 K. For convenience, we take 0° C = 273 K
after rounding off the decimal. To convert a temperature on the Celsius scale to the Kelvin scale we have to add 273 to the given temperature.
(a) 25°C = 25 + 273 = 298 K
(b) 373°C = 373 + 273 = 646 K
This is an answered question from Chapter 1. MATTER IN OUR SURROUNDINGS of Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-86511528813625813322018-01-05T16:08:00.000+05:302018-01-05T16:08:12.478+05:30Convert the following temperatures to the celsius scale. (a) 293 K (b) 470 K.
Answer : As we know 0° C =273.16 K. For convenience, we take 0° C = 273 K after rounding off the decimal.
To change a temperature on the Kelvin scale to the Celsius scale we have to subtract 273 from the given temperature
(a) 293 K = 293-273 = 20° C
(b) 470 K = 470-273 = 197° C
This is an answered question from Chapter 1. MATTER IN OUR Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-79115767527462220282018-01-05T15:54:00.001+05:302018-01-05T15:54:26.441+05:30Which of the following are chemical changes?Question 11 from Chapter 2. IS Matter Around Us Pure ?
(a) Growth of a plant
(b) Rusting of iron
(c) Mixing of iron filings and sand
(d) Cooking of food
(e) Digestion of food
(f) Freezing of water
(g) Burning of a candle
Answer :
(a) Growth of a plant
(b) Rusting of iron
(d) Cooking of food
(e) Digestion of food
(g) Burning of a candle
This is an answered question from Chapter 2. IS Matter Around Us Pure ? of CBSE Class 9thUnknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-17557799225723170052018-01-05T15:53:00.001+05:302018-01-05T15:53:06.754+05:30Classify the following into elements, compounds and mixtures Question 10 from Chapter 2. IS Matter Around Us Pure ?
(a) Sodium
(b) Soil
(c) Sugar solution
(d) Silver
(e) Calcium carbonate
(f) Tin
(g) Silicon
(h) Coal
(i) Air
(j) Soap
(k) Methane
(l) Carbon dioxide
(m) Blood
Answer : Classification of materials as elements, compounds and mixtures.
ElementsCompoundsMixture
(a) Sodium
(d) Silver
(f) Tin
(g) Silicon(e) Calcium carbonate
(k) Methane
(l) Carbon dioxide(b) Soil
Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-37333027273193483732018-01-05T15:50:00.004+05:302018-01-05T15:50:56.329+05:30Which of the following will show "Tyndall effect"? Question 9 from Chapter 2. IS Matter Around Us Pure ?
(a) Salt solution
(b) Milk
(c) Copper sulphate solution
(d) Starch solution.
Answer : Scattering of a beam of light passing through a suspension or a colloidal solution is called the Tyndall effect. Both a suspension and a colloidal solution is a heterogeneous mixture in which the particles which may or may not be seen with naked eyes, can scatter aUnknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-72732337734611600552018-01-05T15:49:00.002+05:302018-01-05T15:49:17.874+05:30Identify the solutions among the following mixtures Question 8 from Chapter 2. IS Matter Around Us Pure ?
(a) Soil
(b) Sea water
(c) Air
(d) Coal
(e) Soda water.
Answer : As we know a solution is a homogeneous mixture of two or more substances. The component of the solution which is present in larger amount and dissolves the other is called solvent and other component with lesser quantity which gets dissolved in solvent is called the solute.
As per the description above, the Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-78615461029725743942018-01-05T15:47:00.002+05:302018-01-05T15:47:43.094+05:30Which of the following materials fall in the category of a "pure substance" ? Question 7 from Chapter 2. IS Matter Around Us Pure ?
(a) Ice
(b) Milk
(c) Iron
(d) Hydrochloric acid
(e) Calcium oxide
(f) Mercury
(g) Brick
(h) Wood
(i) Air.
Answer : A pure substance contains only one kind of pure matter and its composition is the same throughout. Mixtures are constituted by more than one kind of pure substance.A pure substance cannot be separated into other kinds of matter by any physical process.WhateverUnknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-43462151947851239412018-01-05T15:45:00.003+05:302018-01-05T15:45:36.158+05:30 How would you confirm that a colourless liquid given to you is pure water?
Answer : For a given atmospheric pressure, every liquid has a distinct boiling point. Water in its pure form boils at 100° C or 273 K at 1 atmospheric pressure. If given colourless liquid starts boiling below or above 100° C or 273 K, it is either not pure water or some other liquid. So boiling point of a liquid, is an indicator of its purity at aUnknownnoreply@blogger.com1tag:blogger.com,1999:blog-4393894824797662045.post-30241348965727470062018-01-05T15:44:00.002+05:302018-01-05T15:44:37.358+05:30Classify each of the following as a homogeneous or heterogeneous mixture. soda water, wood, air, soil, vinegar, filtered tea.
Answer :
Homogeneous MixtureHeterogeneous Mixture
Soda water
Air
Vinegar
Wood
Soil
Filtered tea
This is an answered question from Chapter 2. IS Matter Around Us Pure ? of CBSE Class 9th Science
Check for Complete
Exercise Solution for Chapter 2. IS Matter Around Us Pure ? | CBSE Class 9th Science
Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-30047123978369211002018-01-05T15:43:00.001+05:302018-01-05T15:43:38.402+05:30Explain the following giving examples Question 4 from Chapter 2. IS Matter Around Us Pure ?
(a) saturated solution
(b) pure substance
(c) colloid
(d) suspension
Answer :
(a) Saturated solution : A solution at any particular temperature, having maximum amount of solute which can be dissolve in it, is called a saturated solution. In other words, at a given temperature no more solute can be dissolved in a saturated solution.
(b) Pure substance : A pure Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-31904613253023225442018-01-05T15:40:00.001+05:302018-01-05T15:40:47.784+05:30Pragya tested the solubility of three different substances at different temperatures and collected the data as given below Question 3 from Chapter 2. IS Matter Around Us Pure ?
(results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).
Substance DissolvedTemperature in K 283 293 313 333 353
Solubility
Potassium nitrate
Sodium chloride
Potassium chloride
Ammonium chloride21
36
35
2432
36
35
3762
36
40
41106
37
46
55167
37
54
66
(a) What Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-36297003230275140352018-01-05T15:37:00.002+05:302018-01-05T15:38:03.906+05:30Write the steps you would use for making tea. Use the words : solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.
Answer : For making tea, first of all we will take desired cups of water as solvent in a tea pan. Then it is allowed to boil on stove. Tea leaves, as salute is added to it and brewed. While brewing , the colour of water as solvent gets changed to tea colour as soluble part of tea as salute gets dissolve in heated water as solvent. There after, milk is added toUnknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-50413584671842533292018-01-05T15:36:00.000+05:302018-01-05T15:36:22.105+05:30Which separation techniques will you apply for the separation of the following?Question 1`Chapter 2. IS Matter Around Us Pure ? from
(a) Sodium chloride from its solution in water.
(b) Ammonium chloride from a mixture containing sodium chloride and ammonium chloride.
(c) Small pieces of metal in the engine oil of a car.
(d) Different pigments from an extract of flower petals.
(e) Butter from curd.
(f) Oil from water.
(g) Tea leaves from tea.
(h) Iron pins from sand.
(i) Wheat grains from husk.
(j) Fine mud Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-78776649629236981912018-01-05T14:53:00.003+05:302018-01-05T15:36:39.990+05:30Calculate the number of aluminium ions present in 0.051 g of aluminium oxide. (Hint: The mass of an ion is the same as that of an atom of the same element. Atomic mass of Al = 27 u)
Answer :
1 mole of Aluminium Oxide (Al2O3) = 2 × 27 + 3 × 16 = 102 gWe know, 102 g of Aluminium Oxide (Al2O3) = 6.022 × 1023 molecules of Aluminium Oxide (Al2O3)
We know, The number of atoms present in given mass = (Given mass ÷ molar mass) × Avogadro number
Then, 0.051 g of Aluminium Oxide (Al2O3) contains
= (0.051 ÷ Unknownnoreply@blogger.com13tag:blogger.com,1999:blog-4393894824797662045.post-2008988295501814102018-01-05T14:52:00.003+05:302018-01-05T14:52:19.909+05:30Calculate the number of molecules of sulphur (S8) present in 16 g of solid sulphur.
Answer :
1 mole of Sulphur (S8) = 8 × 32 g = 256 galso as 1 mole = 6.022 × 1023 in number of particles of that substance
So 256 g of sulphur contains = 6.022 × 1023 molecules of sulphurTherefor 16 g of sulphur will contains = 3.76 × 1022 molecules (approx)
This is an answered question from Chapter 3. Atoms And Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-78387379456727648012018-01-05T14:50:00.004+05:302018-01-05T14:50:59.529+05:30What is the mass of Question 9 from Chapter 3. Atoms And Molecules
(a) 0.2 mole of oxygen atoms?
(b) 0.5 mole of water molecules?
Answer : Mass of atoms (m) in given moles (n) = Molar Mass of substance (M)× Given Moles of substance (n)
(a) ∴ Mass of 0.2 mole of oxygen atoms = Molar Mass of oxygen × Given Moles = 16g × 0.2 = 3.2 g(b) ∴ Mass of 0.5 mole of water Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-46568451554262044532018-01-05T14:49:00.002+05:302018-01-05T14:49:35.292+05:30 Convert into mole Question 8 from Chapter 3. Atoms And Molecules
(a) 12 g of oxygen gas
(b) 20 g of water
(c) 22 g of carbon dioxide.
Answer: To get the mass of 1 mole of atom of that element, that is, molar mass, we have to take the same numerical value but change the units from 'u' to 'g'.
∴ 1 mole substance = Total Atomic mass of a substance (u) Or
&Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4393894824797662045.post-57357547699468572062018-01-05T14:48:00.000+05:302018-01-05T14:48:02.717+05:30What is the mass of Question 7 from Chapter 3. Atoms And Molecules
(a) 1 mole of nitrogen atoms?
(b) 4 moles of aluminium atoms (Atomic mass of aluminium= 27)?
(c) 10 moles of sodium sulphite (Na2SO3)?
Answer :The mass of 1 mole of a substance is equal to its relative atomic or molecular mass in grams. The atomic mass of an element gives us the mass of one atom of that element in atomic mass units (u). To get the mass of 1 mole of atom of that element, Unknownnoreply@blogger.com0