CBSE Class IX [Chemistry] Guess Questions 2nd Summative Assessment 2013-14

 Guess Questions 2nd Summative Assessment 2012-13 SET-01 [Chemistry]

1. Calculate number of moles in 34 g of NH3 (Given atomic mass of N= 14 u; H= 1 u)?[2]

2. Write chemical formulas of :(a) Sodium Carbonate (b)Ammonium Chloride[2]

3. (a) Write a chemical formula of a compound using zinc ion and phosphate ion. (b) Calculate the ratio by mass of atoms present in a molecule of carbon dioxide (Given C=12, O=16)[2]

4. (a) State the law of Definite proportion with an example.(b)  Give any two limitations of Dalton’s Atomic Theory.         [3]

5. Calculate number of atoms in 120 g of Ca :( atomic mass of Ca= 40u) [3]

6. (a)Write the symbol and name of the element having 14 protons.

(b) Complete the table.

Element	Atomic No	Mass No	Proton	Neutron
Cl	17	-	-	18
Si	-	28	-	-
F	-	-	9	10

(c) Give one drawback of Rutherford model. [3]

7 .(a)The average atomic mass of a sample of an element X is 16.2u.What are the  percentage of isotope ¹⁶X₈ and ¹⁸X₈ in the sample.(b)On the basis of Thomson’s model of an atom explain how the atom is neutral as a whole.[5]

8. (a) Explain the following terms : (i)Isotopes (ii) Isobars[2]

(b) A gas jar contains 1.7 g of ammonia gas. Calculate the following: [3](i) Molar mass of Ammonia.  

(ii)How many moles of ammonia are present in the gas - jar? (iii)How many molecules of ammonia are 
present in the sample?

9.(a)Describe briefly Thomson’s model of an atom.(b) Who discovered Neutron ? (c) What are Canal Rays? (d)What is the mass of proton as compared to electron? [5]

Guess Questions 2nd Summative Assessment 2012-13 SET-02 [Chemistry]

1. Calculate mass of 3.011X10²³ number of nitrogen atoms ( Atomic Mass of N =14 u ) ?[2]

2. Write two peculiar characters of sponges?[2]

3. If the symbolic representation of an atom is ⁶X₃, what is its valency, name and also give the reason for the 
valency?[2]

4. (a) Define the term molecular mass.(b) State and explain law of conservation of mass with example.[3]

5. Calculate :-(a)(i)Number of molecules in 90g of H2   ?(ii)Number of moles in 19g of H₂O₂ ?(b) (b) Define the term mole.[3]

6. Name the two laws of chemicals combinations and write the statement of each one of them.[3]

7.(a) Explain the following with one example of each.(i) Atomic number    (ii) Mass number

 (b)Give the distribution of electrons in sodium and chlorine atom.[5]

8. (a) Draw the diagram of Rutherford’s alpha scattering experiment.(b)  What were three observations of this experiment ?[2+3=5]

9. (a)Why the chemical properties of isotopes are same ?(b) Draw Bohr model for helium atom.(c) What are the no. of protons, neutrons and electrons in ⁵⁹Co ₂₇  and ¹⁰⁸ Ag₄₇ 

10.Questions:   On the basis of the number of protons, neutrons and electrons in the samples given below identify (a) the cation (b) the pair of isobars and (c) the pair of isotopes.

Sample	Protons	Neutrons	Electrons
A	17	18	16
B	18	19	18
C	17	20	17
D	17	17	17

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Guess Questions 2nd Summative Assessment 2012-13
Sample Paper Summative Assessment- II, March 2013