Which of the following
[question] Question. Which of the following are chemical changes ? (a) Growth of a plant (b) Rusting of iron (c) Mixing of iron fillings and sand (d) Cooking of food (e) Digestion of food (f) Freezing of water (g) Burning of a candle [/question] [solution] Solution: Rusting of iron, cooking of food, digestion of food, and burning of candle are chemical changes. [/solution]...
Classify the following into elements,
[question] Question. Classify the following into elements, compounds and mixtures. (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 [/question] [solution] Solution: Elements : sodium, silver, tin and silicon Compounds : calcium carbonate, soap, methane and carbon dioxide Mixtures : soil, sugar solution, coal, air and blood. [/solution]...
Which of the following will show
[question] Question. Which of the following will show "Tyndall effect" ? (a) Salt solution (b) Milk (c) Copper sulphate solution (d) Starch solution [/question] [solution] Solution: Colloids show Tyndall effect, Milk is a colloid. Thus, it will show Tyndall effect. Therefore the correct answer is (b). [/solution]...
Identify the solution among
[question] Question. Identify the solution among the following mixtures (a) Soil (b) Sea water (c) Air (d) Coal (e) Soda water [/question] [solution] Solution: Sea water, air, and soda water are solutions [/solution]...
Which of the following materials fall in the category
[question] Question. Which of the following materials fall in the category of a "pure substance" ? (a) Ice (b) Milk (c) Iron (d) Hydrochloric acid (e) Calcium oxide (f) Mercury (g) Bric (h) Wood (i) Air. [/question] [solution] Solution: Ice, iron, hydrochloric acid, calcium oxide, and mercury are pure substances. [/solution]...
How would you confirm that a colourless liquid
[question] Question. How would you confirm that a colourless liquid given to you is pure water ? [question] [solution] Solution: If the boiling and freezing points of the given liquid comes out to be 100°C and 0°C respectively under one atmosphere pressure, it confirms that the given liquid is pure water [/solution]...
Classify each of the following as a homogeneous
[question] Question. Classify each of the following as a homogeneous or heterogeneous mixture. soda, water, wood, air, soil, vinegar, filtered tea. [/question] [solution] Solution: Homogeneous – soda, water, air, vinegar, filtered tea. Heterogeneous – wood, soil. [/solution]...
Explain the following by giving examples
[question] Question. Explain the following by giving examples (a) Saturated solution (b) Pure substance (c) Colloid (d) Suspension [/question] [solution] Solution: (a) At any particular temperature, a solution that has dissolved as much solute as it is capable of dissolving is said to be a saturated solution. Few examples of saturated solutions are soft drinks and nitrogen in Earth's soil. (b) A pure substance is one that cannot be separated into different constituents by physical or chemical pr...
Pragya tested the solubility of three different substances at different
[question] Question. Pragya tested the solubility of three different substances at different temperatures and collected the data as given below. Result are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution. (a) Potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K ? (b) Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to co...
Write the steps you would use for making tea.
[question] Question. Write the steps you would use for making tea. Use the words solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue. [/question] [solution] Solution: Take some water in pan. Keep the pan over flame. The solutes tea leaves & sugar should be added to a pan containing water as solvent. Heat the water over the pan till the sugar, which is soluble in water dissolves in it. Tea leaves are insoluble in water and will remain suspended. Now add water to the suga...
Try segregating the things around
[question] Question. Try segregating the things around you as pure substances or mixtures : (a) distilled water (b) curd (c) diamond (d) ice-cream (e) kerosene oil (f) cooking oil (g) steel (h) graphite (i) raw rubber (j) vulcanized rubber (k) solder wire (l) glass (m) iron nail. [/question] [solution] Solution: (i) Pure substances : distilled Water, glass, iron nail, graphite, diamond, raw rubber. (ii) Mixture : curd, ice cream, kerosene oil, cooking oil, steel, vulcanized rubber, solder wire. ...
Classify the following as chemical
[question] Question. Classify the following as chemical or physical changes : • Cutting of trees • Melting of butter in a pan • Rusting of almirah • Boiling of water to form steam • Passing of electric current through water and the water breaking down into hydrogen and oxygen gases • Dissolving common salt in water • Making a fruit salad with raw fruits, and • Burning of paper and wood. [/question] [solution] Solution: Physical changes : Cutting of trees, melting of butter in a pan, boiling wate...
What type of mixtures are separated
[question] Question. What type of mixtures are separated by the technique of crystallisation? [/question] [solution] Solution: The crystallisation method is used to purify solid mixtures. [/solution]...
Name the technique to separate,
[question] Question. Name the technique to separate, (i) Butter from curd, (ii) Salt from sea-water, (iii) Camphor from salt. [/question] [solution] Solution: (i) Centrifugation (ii) Evaporation (iii) Sublimation [/solution]...
How will you separate a mixture containing kerosene
[question] Question. How will you separate a mixture containing kerosene and petrol (difference in their boiling points is more than 25°C), which are miscible with each other? [/question] [solution] Solution: The process of distillation is used for the separation of components of a mixture containing two miscible liquids that boil without decomposition and have sufficient difference in their boiling points (that is greater than 25°C). [/solution]...
To make a saturated solution,
[question] Question. To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature. [/question] [solution] Solution: Concentration $=\frac{\text { Mass of solute }}{\text { Mass of solution }} \times 100$ Here, mass of solute = 36 g and mass of solvent = 100 g Therefore, Mass of solution $=100+36=136 \mathrm{~g}$ Thus, concentration $=\frac{36}{136} \times 100=26.47 \%$ [/solution]...
Differentiate between homogeneous
[question] Question. Differentiate between homogeneous and heterogeneous mixtures with examples. [/question] [solution] Solution: Homogeneous mixture They contain physically distinct parts and have non-uniform compositions. Mixtures of sodium chloride and iron fillings, salt and sulphur, and oil and water are examples of heterogeneous mixtures. Suspensions and colloids are also heterogeneous mixtures. Heterogeneous mixture : They contain physically distinct parts and have non-uniform composition...
List the points of differences between
[question] Question. List the points of differences between homogeneous and heterogeneous mixtures] [/question] [solution] Solution: Homogeneous mixture : (i) The composition of a homogeneous mixture is the same throughout. For example, if you make a solution of sugar in water and taste it by taking a spoonful of solution either from the surface or from somewhere underneath the surface, it tastes equally sweet. (ii) A homogeneous mixture has no distinct boundaries, i.e., it consists of only one ...
What is meant by a pure substance?
[question] Question. What is meant by a pure substance? [question] [solution] Solution: A pure substance is one that cannot be separated into different constituents by physical or chemical process. A pure substance is one that contains particles of only one type of a substance. [/solution]...