CHEMISTRY TEST PAPER

M.M.50 Marks

Time: 3.30 Hr.Topic: 1.Some Basic Concept-30 Marks

2. Atomic structure

-20 Marks

1. 1 to 5 question - 1 marks = 5 marks

2. 6 to 14 question - 2 marks = 18 marks

3. 15 to 23 question 3 marks = 27 marks

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1. What is the SI unit of electric current?

2. Express the following in the scientific notation:

(a) 0.0048 (b) 500.0

3. How many significant figures are present in the following:

(a) 0.0025 (b) 3.0024

4. How many electrons, protons and neutrons are there in ?

5. Calculate the mass and charge of one mole of electron?

6. Calculate the mass percent of different elements present in sodium bi carbonate ?

7. Calculate the concentration of nitric acid in moles of nitric acid in moles per liters in a sample which has density, and the mass percent in nitric acid is 69%.

8. How much sulphur can be obtained from 300 gm of .

9. Mass of one drop of water is 0.05 g. Calculate the number of molecules are present in it.

10. At S.T.P, if the mass of 94.5 ml gas is 0.2231 then calculate mol weight of gas.

11. Yellow light is emitted from a sodium lamp has a wave length 920 pm. Calculate the frequency and wave number of the yellow light.

12. A 25-watt bulb emits monochromatic yellow light of wavelength of 0.57 . Calculate the rate of emission of quantum per second.

13. The mass of an electron is kg. If its K.E. is calculates its debroglie wavelength.

14. An element with mass number 81 contains 31.7% more neutrons as compared to protons. Calculate the number of electron and neutron.

15. A mixture of 1.0 mol of Al and 3.0 mol of Cl2 are allowed to react as :

(a) Which is limiting reagent?

(b) How many moles of are formed.

(c) Moles of excess regent left un - reacted.

16. A wielding fuel gas contains carbon and hydrogen only. Burning a small sample of it in oxygen gives 3.38 g carbon dioxide, 0.690 g of water and no other products. A volume of 10.0 L of this welding gas is found to weigh 11.6 g. Calculate: -

(a) empirical formula (b) molar mass(c) molecular formula

17. 32% by mass glucose in aqueous solution. Find morality and mole fraction of solute and solvent if density of solution in 1.4 gm/cm3. .

18. Find the mass of the following substances: -

(a) 1.4 g atom of N (b) atom of Carbon(c) 1.12 liter of O2 at S.T.P.

19. Naturally occurring chlorine is 75.53% Cl35 which has an atomic mass of 34.969 amu and 24.47% Cl37, which has a mass of 36.966 amu. Calculate the average atomic mass of chlorine.

20. A photon of wave length strikes on metal surface, the work function of the metal being 4.2 ev calculate: -

(a) The energy of the proton.

(b) Kinetic energy of electron.

(c) Velocity of electron.

21. Find the value of n, l, m, s for 19th electron in chromium atom.

22. What is the wavelength of light emitted when the electron in a hydrogen atom undergoes transition from an energy level with n = 4 to an energy level with n = 2?

23. Carbon and oxygen are known to form two components. The carbon content in one of these is 42.9% while in the other it is 27.3%. Show that this data is in agreement with the Law of Multiple Proportions.

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