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Class 9 Science CBSE Objective type for Atoms and Molecules






Given below are the Class 9 Science CBSE Objective type for Atoms and Molecules
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Multiple Choice Questions


1.Which of the following has largest number of particles?
a)8g of CH4
b)4.4g of CO2
c)34.2g of C12H22O11
d)2g of H2
2.The number of molecules in 16.0g of oxygen is:
a)6.02 x 1023
b)6.02 x 10-23
c)3.01 x 10-23
d)3.01 x 1023
3. The percentage of hydrogen inH2 Ois:
a)8.88
b)11.12
c)20.60
d)80.0
4. Find the mass of oxygen contained in 1 kg of potassium nitrate (KNO3)
a)475.5g
b)485.5g
c)475.2g
d)485.2g
5. How many moles of electron weight one kilogram?
a)6.023 x 1023
b)1/9.108 x 6.023 X 108
c)6.023/9.108 x 1054
d)1/ 9.108 x 6.023 x 108
6. 25.4g of iodine and 14.2g of chlorine are made to react completely to yield a mixture of CI and ICI3. Calculate the ratio of moles of ICI and ICI3:
a)1: 1
b)2: 1
c)3: 1
d)1: 2
7. The mass of sodium n 11.7 g of sodium chloride is:
a)2.3g
b)4.6g
c)6.9g
d)7.1g
8. The formula of a chloride of a metal M is MCl3, the formula of the phosphate of metal M will be:
a)MPO4
b)M2PO4
c)M3PO4
d)2(PO4 )3
9.Which of the following contains the largest number of molecules?
a)0.2 mol H2
b)8.0g H2
c)17g of H2 O
d)6.0 g of CO2
10. One gram of which of the following contains largest number of oxygen atoms?
a)O
b)O2
c)O3
d)All contains same
11.The percentage by weight ofO2 in CaO4 ( O = 16, S = 32, Ca = 40) is:
a)64
b)28.2
c)47.2
d)16.2
12. The percentage by weight of Zn in white vitriol, ZnSO4.7H2O (Zn = 65, S = 32, O = 16, H = 1), is approximately:
a)23
b)33
c)43
d)13
13.The formation of SO2 and SO3 explain:
a)The law of conservation of mass
b)The law of multiple proportions
c)The law of definite properties
d)Boyle’s law
14.The law of definite proportions was given by:
a)John Dalton
b)Humphry davy
c)Proust
d)Michael Faraday
15.Molecular mass is defined as the:
a)Mass of one atom compared with the mass of one molecule
b)Mass f one atom compared with the mass of one atom of hydrogen
c)Mass of one molecule of any substance compared with the mass of one atom of C – 12
d)None of the above
16.0.001 g of C is required t write a letter with a graphite pencil. The total number of C atoms used in writing the letter is:
a)5.00 x 1012
b)5 x 1019
c)5.0 x 1024
d)6.023 x 1023
17.One mole of a gas occupies a volume of 22.4 L. This is derived from:
a)Berzelius’s hypothesis
b)Gay- Lussac’s law
c)Avogadro’s law
d)Dalton’s law
18.The mass of one C atom is:
a)6.023 x 1023 g
b)1.99 x 10-23g
c)2.00 g
d)12 g
19.The chemical symbol for barium is:
a)B
b)Ba
c)Be
d)Bi
20.The chemical symbol P stands for:
a)Phosphorus
b)Potassium
c)Polonium
d)Promethium
21.A group of atoms chemically bonded together is a (an):
a)Molecule
b)On
c)Salt
d)Element
22.Adding electrons to an atom will result in a (an):
a)Molecule
b)Anion
c)Cation
d)Salt
23.When an atom loses electrons, it is called a (an) ______ and has a _____ charge.
a)Anion, positive
b)Cation, positive
c)Anion, negative
d)Cation, negative
24.The molecule formula P2O5 means that:
a)A molecule contains 2 atoms of P and 5 atoms of O
b)The ratio of the mass of P to the mass of O in the molecule is 2:5
c)There are twice as many P atoms in the molecule as there are O atoms
d)The ratio of the mass of P to the ass of O in the molecule is 5:2
25.The correct symbol for silver is:
a)Ag
b)S
c)Ar
d)AI
26.A spartame, an artificial sweetener, has the molecular formula C14H18N2O5. What is the mass in grams of one molecule? (Atomic weights: C = 12.01, H = 1.008, N = 14.01, O = 16.00).
a)4.89 x 10-21
b)2.24 x 10-21
c)3.85 x 10-22
d)4.89 x 10-22
27.Morphine, an addictive drug, has the molecular formula C17H19NO3. What is the mass in grams of one molecule?(Atomic weights: C = 12.01, H = 1.008, N = 14.)1, O = 16.00).
a) 2.24x 10-22
b) 3.85 x 10-22
c) 3.85 x 10-21
d) 4.74 x 10-22
28. The controversial artificial sweetener saccharin has the molecular formula C3H5O5NS. What is the mass in grams of one molecule? Atomic weights: C = 12.01, H = 1.008, O = 16.00, N = 14.01, S = 32.06).
a)5.55 x 10-21
b)3.85 x 10-22
c)2.24 x 10-22
d)2.24 x 10-21
29.The statue of Liberty is made of 2.0 x 105 Ibs of copper sheets bolted to a framework. (1Ib = 454 g ) How many atoms of copper are on the statue? (Atomic weight: Cu = 63.5).
a)2.1 x 1027
b)8.6 x 1029
c)4.3 x 1026
d)8.6 x 1026
30. Selenium ingested in the amount of 90 microgarms per day causes loss of hair. How many selenium atoms are n this size sample? (Atomic weight: Se = 78.96).
a)6.9 x 1023
b)8.8 x 1017
c)8.8 x 1022
d)6.9 x 1017
31. Novocain is C13H16N2O2 What is the total number of moles of atoms in 0.020 moles of Novocain?
(Atomic weights: C = 12.01, O = 16.00, N = 14.01, H = 1.008).
a)0.033
b)3.3
c)0.66
d)0.33
32. Methoxychlor, a garden insecticide, has the molecular formula C16H15C13O. What is the total number of moles of atoms in a 3.0 mg sample? (Atomic weights: C = 12.01, H = 1.008, CI = 35.45, O = 16.00).
a)8.7 x 10-6
b)3.0 x 10-5
c)3.1 x 10-1
d)3.1 x 10-4
33. What are the total number of moles of atoms in 4.32 g of Sc(NO3)3?
(Atomic weights: Sc = 45.0, O = 16.00, N = 14.01).
a)0.0132
b)0.324
c)0.0187
d)0.243
34. Two samples of lead oxide were separately reduced to metallic lead by heating in a current of hydrogen. The weight of lead from one oxide was half the weight of lead obtained from the other oxide. The data illustrates:
a)Law of reciprocal proportions
b)Law of constant proportions
c)Law of multiple proportions
d)Law of equivalent proportions
35. The percentage of copper and oxygen in samples of CuO obtained by different methods were found to be the same. The illustrate the law of:
a)Constant proportion
b)Conservation of mass
c)Multiple proportions
d)Reciprocal proportions
36. The total number of atoms represented by the compound CuSO4.5H2O is:
a)27
b)21
c)5
d)8
37. In compound A, 1.00g of nitrogen unites with 0.57 g of oxygen. In compound B, 2.00g of nitrogen combines with 2.24g of oxygen. In compound C, 3.00g of nitrogen combines with 5.11g of oxygen. These results obey the following law:
Law of constant proportion
Law of multiple proportion
Law of reciprocal proportion
Dalton’s law of partial pressure
38. The weight of a molecule of the compound C60H122 is:
a)1.4 x 10-21 g
b)1.09 x 10-21 g
c)5.025 x 1023 g
d)16.023 x 1023 g
39. The mass of a molecule of water is:
a)3 x 10-26 kg
b)3 x 10-25 kg
c)1.5 x 10-26 kg
d)2.5 x 10-26 kg
40. The number of atom in 4.25g of NH3 is approximately:
a)1 x 1023
b)2 x 1023
c)4 x 1023
d)6 x 1023
41. Volume of a gas at STP is 1.12 x 10-7 cc. Calculate the number of molecules in it:
a)3.01 x 1020
b)3.01 x 1012
c)3.01 x 1023
d)3.01 x 1024
42. The number of molecules of CO2 present in 44g of CO2 is:
a)6.02 x 1023
b)3 x 1023
c)12 x 1023
d)3 x 1010
43. The volume occupied by 4.4g of CO2 at STP is:
a)22.4 L
b)2.24 L
c)0.224 L
d)0.1 L
44. How many molecules are present in one gram of hydrogen?
a)6.02 x 1023
b)3.01 x 1023
c)2.5 x 1023
d)1.5 x 1023

ANSWERS:

1.(d)
2.(d)
3.(b)
4.(b)
5.(d)
6.(a)
7.(b)
8.(a)
9.(b)
10.(c)
11.(c)
12.(a)
13.(b)
14.(c)
15.(c)
16.(b)
17.(c)
18.(b)
19.(b)
20.(a)
21.(a)
22.(b)
23.(b)
24.(a)
25.(a)
26.(d)
27.(d)
28.(c)
29.(b)
30.(d)
31.(c)
32.(d)
33.(d)
34.(c)
35.(a)
36.(b)
37.(b)
38.(a)
39.(a)
40.(d)
41.(b)
42.(a)
43.(b)
44.(b)

 



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