IX Practical Chemistry KBSE Experiment No. 1

To determine the density of Glycerine / Kerosine Oil / Saturated Solution of common salt using R.D. Bottle

Viva Voce
Qs. 1. What is the chemical formula of common salt?

Ans. The chemical formula of common salt is NaCl.


Q.2. Which elements are present in common salt?

Ans. Common salt contains sodium and chlorine elements.


Q.3. What is the chemical name of Common salt?

Ans. The chemical name of Common salt is Sodium Chloride.


Q.4. What is the molecular weight of Sodium Chloride?

Ans. The molecular weight of Sodium Chloride is 58.5.


Q.5. What is the atomic weigth of Sodium?

Ans. The atomic weight of Sodium is 23.


Q.6. What is the atomic weigth of Chlorine?

Ans. The atomic weight of Sodium is 35.5.


Q.7. What do you understand by solute?

Ans. Anything which dissolves in a liquid is called Solute.

OR

Solution comprises of two constitiuents. That constituent which is less in quantity is called Solute.


Q.8. What is the name of that constituent which is present in smaller amount in the solution?

Ans. The constituent present in smaller point is called Solute.


Q.9. What is Solvent?

Ans. Any substance which can dissolve a substance to form a homogeneous mixture is called a solvent.

OR

The component of the solution present in greater amount is called Solvent.

EXAMPLE: When sodium chloride is dissolved in water then the water is known as Solvent.


Q.10. What do you understand by the term Solution?

Ans. A homogeneous mixture of two or more substances is called solution.

EXAMPLE: Homogeneous mixture of sugar and water is called solution.


Q.11. What is Solubility?

Ans. The Solubility of a substance can be defined as the amount of the substance that can be dissolved by 100 gms of the solvent at a particular temperature. Mathematically it can be expressed as

Solubility = Weight of solute in gm / Weight of Solvent in gm x 100


Q.12 What is Density?

Ans. Mass per unit volume of substance is called Density.


Q.13 What is the unit of density in M.K.S System?

Ans. gm/cm3 or gm/ml


Q.14. What is the unit of density in M.K.S System?

Ans. Kilogram/m3 or Kilogram/litre.


Q.15. What is the unit of density in British Engineering System?

Ans. Slug/(foot)3 or Slug per cubic foot.


Q.16. What is Mass?

Ans. The quantity of matter present in a substance is called its Mass.


Q.17. What is the unit of mass in C.G.S System?

Ans. Gram.


Q.18. What is the unit of mass in M.K.S. System?

Ans. Kilogram.


Q.19. What is the unit of mass in B.E.System?

Ans. Slug.


Q.20. What is Volume?

Ans. The space occupied by the substance is called its volume?


Q.21. What is the unit of volume in C.G.S system?

Ans. Cm3 or C.C.


Q.22. What is the unit of Volume in M.K.S System?

Ans. The unit of Volume in M.K.S System is (Metre)3 or Cubic Metre.


Q.23. What is the unit of Volume in B.E.System?

Ans. (Foot)3.


Q.24. What do you understand by Weight?

Ans. The force of attraction of the earth exerted on an object is called its weight.


Q.25. What is the unit of weight in M.K.S.System?

Ans. Newton.


Q.26. What is the unit of weight in C.G.S System?

Ans. Dyne.


Q.27. What is the unit of weight in B.E.System?

Ans. Pound.


Q.28. What is meant by Relative Density?

Ans. The ratio of the density of a substance to the density of water at 4oC is called its Relative Density.


Q.29. How will you express the formula of Relative Density mathematically?

Ans. Relative Density = Density of Substance / Density of water at 4oC


Q.30. What is the formula of Relative Density of Substance in terms of Mass of the Substance?

Ans. Relative Density = Mass of Substance / Mass of equal volume of water.


Q.31. What is the unit of Relative Density?

Ans. It has got no unit because it is a ratio.


Q.32. What is the density of water at 4oC?

Ans. The density of water at 4oC is 1 gm/cm3.


Q.33. Why do we consider the density of water at 4oC?

Ans. We consider the density of water at 4oC because it is maximum at this temperature.


Q.34. What is Specific Gravity?

Ans. Specific Gravity of a substance is the ratio of the density of a substance to the density of water at 4oC.


Q.35. What is the unit of Specific Gravity?

Ans. It has got no unit because it is a ratio.


Q.36. What is R.D.Bottle?

Ans. It is a small bottle of known Capacity having a glass stopper possessing fine hole used for finding the volume of liquid.


Q.37. What is the use of the density of a substance?

Ans. By the knowledge of the densities we identify different substances.


Q.38. How do you clean the R.D.Bottle?

Ans. R.D.Bottle is cleaned by Alcohal or Ether.


Q.39. Why is it advised to remove air bubbles from R.D.Bottle?

Ans. If the air bubbles are not removed then there will be loss in weight of Salt Solution.


Q.40. Which instrument is used for determining the mass of the substance?

Ans. Physical Balance is used for determining the mass of the substance?


Q.41. Which instrument is used for determining the weight?

Ans. Spring Balance is used for determining the weight of a substance.


Q.42. How do you find the Volume of Salt Solution?

Ans. As we talk Salt Solution in R.D.Bottle so its volume will be equal to the volume of the bottle mentioned on it.


Q.43. What is the difference between Mass and Weight?

Ans. MASS:

1. The quantity of matter present in a substance is called Mass.

2. Mass remains the same at all the places.

3. Mass is measured with a Physical Balance.

4. The unit of Mass in various systems of measurements is given below.

C.G.S. System _______ Gram

M.K.S. System _______ Kilogram

B.E. System _________ Slug

WEIGHT:

1. The force of attraction of the earth exerted on a substance is called its weight.

2. Weight changes as the distance from the centre of the earth changes.

3. Weight is determined with the help of Spring Balance.

4. The unit of weight in various systems of measurements is given below.

C.G.S. System _______ Dyne

M.K.S. System _______ Newton

B.E. System _________ Pound


Q.44. Does the weight of a substance remain the same at all the places or changes. Give the reason why does it happen?

Ans. The weight does not remain same at all the places. Weights depends upon the distance of substance from the centre of the earth.


Q.45. Which will occupy more space. 10 C.C of Cotton OR 10 C.C of Iron?

Ans. Both will occupy the same space.


Q.46. Which will have more mass. 20 C.C of Cotton OR 20 C.C of Iron?

Ans. 20 C.C of Iron will have more mass.


Q.47. Which will have more mass. 10 gm of Cotton OR 10 gm of Iron?


Ans. Both will have the same mass.


Q.48. Will the density of a substance be more or less on the mountain as compared to sea level?

Ans. There will be no change in the density.


Q.49. Which is heavier 20 gm of Iron or 20 gm of Cotton?

Ans. Both will have the same weight.


Q.50. Which will be denser 10 gm of Iron or 10 gm of Cotton?

Ans. Iron will be more denser. (In the question we are concerned with the density of the substance).


Q.51. Which kind of lever is the Physical Balance?

Ans. It is first kind of lever.


Q.52. What are the important parts of Physical Balance?

Ans. The important parts of Physical Balance are given below:

1. Beam

2. Adjusting Screws

3. Knife Edges

4. Stirrup

5. Pan

6. Vertical Pillar

7. Pointer

8. Scale

9. Plumb Line or (Spirtit Level)

10. Levelling Screws

11. Knobs


Q.53. What do you understand by the beam ofa Physical Balance?

Ans. The Beam is a horizontal frame work capable of turning freely with very little friction about an "Agate Knife Edge" at the centre called Fulcrum.


Q.54. How many Knife Edges are there in the Physical Balance?

Ans. There are three Knife Edges. One at the middle and two at the ends.


Q.55. What is the purpose of "Plumb Line"?

Ans. The purpose of the Plumb Line is to make the "Pillar" vertical and "Base" horizontal.


Q.56. Why is it advised that when "Balance" is not in use should not be raised too much?

Ans. The sharpness of the Knife Edge is preserved.


Q.57. What should be done if the Plumb Line is broken?

Ans. In such case the spirit level is used to test the level of the base of Physical Balance.


Q.58. Why do we place the "Physical Balance" in a glass case?

Ans. It is kept in glass case to prevent it from being disturbed by wind when weighing is going on and from being contaminated with Acid fumes and moisture.


Q.59. What are the conditions to be satisfied by a good balance?

Ans. A good balance must satisfy the following conditions. It must be

1. True

2. Sensitive

3. Stable


Q.60. On the Specific Gravity bottle, 25 ml, 50 ml and 20oC is written. What do you mean by that?

Ans. 25 ml and 50 ml means 25 Mililitre and 50 Mililitre which indicates the volume of the bottle. 20oC is the temperature at which the volume of that particular bottle is 25 ml or 50 ml.


Q.61. What is the Physical Balance?

Ans. It is the instrument for comparing the mass of an object with a known mass.


Q.62. What is the "Principle of Balance"

Ans. It works on the principle of First kind of Lever.


Q.63. On which pan do you place the weights?

Ans. The weights are placed on the right band.


Q,64. How will you find the density of the milk?

Ans. The density of the milk is determined by a special Hydrometer.


Q.65. What is the practical application of density?

Ans. It helps us to find whether the substance is pure or impure.


Q.66. What is the function of a Hydrometer?

Ans Hydrometer is used for finding the density of a liquid.


Q.67. What will be effect of density of a stone if it is broken into two pieces?

Ans. It will remain the same.


Q.68. Convert 865 milligrams into gram?

Ans. 965 m.gm = .865 gm


Q,69. Convert 75 milligram into gram?

Ans. 75 milligram = .075 gm.


Q.70. Convert 7 milligram into gram?

Ans. 7 milligram = .007 gram.


Q.71. How many C.C are there in one Litre?

Ans. 1000 C.C = One Litre.


Q.72. How many Milligrams are there in one gram?

Ans. 1000 mg = 1 gm.


Q.73. How many ml are there in one litre?

Ans. 1000 ml = 1 Litre.


Q.74. Why do we prefer Ether or Alcohal for rinsing the R.D.Bottle?

Ans. Ether and Alcohal evaporate quickly.


Q.75. Why does Kerosene Oil float on water?

Ans. Kerosene oil float on water because it is lighter than water.


Q.76. Why Kerosene Oil is lighter than water?

Ans. The Kerosene oil is lighter than water because its density is less than the density of water.


Q.77. Convert 5.24 gm into Milligram?

Ans. 5.24 gm = 5240 Milligram.