Class 11 Chemistry Chapter -1 Some Basic Concepts of Chemistry MCQs

Questions
1 Which of the following pairs have the same number of atoms?
A 16 g of O2(g) and 4 g of H2(g)
B 16 g of O2 and 44 g of CO2
C 28 g of N2 and 32 g of O2
D 12 g of C(s) and 23 g of Na(s)

Answer:(C), (D)
2 1 Mole of CH4 contains
A 6.02×1023 atoms of H
B 4 gm-atoms of hydrogen
C 1.81×1023 molecules of CH4CH4
D 3g of Carbon

Answer: 4 gm-atoms of hydrogen
3 A measured temperature on Fahrenheit scale is 200 °F. What will this reading be on Celsius scale?
A 40 °C
B 94 °C
C 93.3 °C
D 30 °C

Answer:93.3 °C
4 Which of the following has the largest number of atoms
A 0.5 g-atoms of Cu
B 0.635 g Cu
C 0.25moles of Cu atoms
D 1g of Cu

Answer:0.5 g-atoms of Cu
5 The number of Gram molecules of oxygen in 6.02×1024 CO molecules is
A 10 gm-molecules
B 5 gm-molecules
C 1 gm -molecules
D .5 gm-molecules

Answer: 5 gm-molecules
6 How many mL of water must be added to 200 mL of .65 M HCL to dilute the solution to .20 M
A 450 mL
B 400 mL
C 350 mL
D 500 mL

Answer: 450 mL
7 Which of the following reactions is not correct according to the law of conservation of mass.
A 2Mg(s)+O2(g)→2MgO(s)
B C3H8(g)+O2(g)→CO2(g)+H2O(g)
C P4(s)+5O2(g)→P4O10
D CH4(g)+2O2(g)→CO2(g)+2H2O(g)

Answer: C3H8(g)+O2(g)→CO2(g)+H2O(g)
8 How many gram of solute is required to prepare 1.0 L of 1 M CaCl2.6H2O?
A 200 g
B 216 g
C 219 g
D None of the above

Answer: 219 g
9 the mass of 2.044×1023 carbon atoms.
A 12 g
B 36 g
C 24 g
D 48 g

Answer:24 g
10 What will be the molarity of a solution, which contains 5.85 g of NaCl(s) per 500 mL?
A 4 mol/L
B 20 mol/L
C 0.2 mol/L
D 2 mol/L

Answer:0.2 mol/L
11 Calculate the number of oxygen atoms in 50 g of CaCO_3.
A 6.033×1023 atoms
B 9.033×1023 atoms
C 8.033×1023 atoms
D 3.033×1023 atoms

Answer:9.033×1023 atoms
12 Calculate the standard molar volume of oxygen gas. The density of O2 gas at NTP is 1.429g/L.
A 22.39litres
B 21.2 Litres
C 24 Litres
D None of the above

Answer:22.39litres
13 Which of the following statements about a compound is incorrect?
A A molecule of a compound has atoms of different elements.
B A compound cannot be separated into its constituent elements by physical methods of separation.
C A compound retains the physical properties of its constituent elements.
D The ratio of atoms of different elements in a compound is fixed

Answer:A compound retains the physical properties of its constituent elements.
14 The percentage of Carbon is Ca(HCO3)2 is
A 15%
B 1.8%
C 14.8%
D 15.2%

Answer:14.8%
15 Calculate the number of Moles of Cu(c2H3o2)2 present in 200 g
A 1.1 mol
B 1 mol
C .9 mol
D 1.2 mol

Answer: 1.1 mol
16 What will be the molality of the solution containing 18.25 g of HCl gas in 500 g of water?
A 0.1 m
B 1 M
C 0.5 m
D 1 m

Answer: 1 m
17 How many moles of atom are contained in 32.7 g of Zn
A .200
B .500
C 1.50
D .0118

Answer: .500
18 Number of significant Figures in the numer 1.065
A 3
B 4
C 2
D 1

Answer:4
19 16 g of oxygen has same number of molecules as in
A 16 g of CO
B 28 g of N2
C 14 g of N2
D 1.0 g of H2

Answer: (C), (D)
20 Which of the following terms are unitless?
A Molality
B Molarity
C Mole fraction
D Mass percent

Answer:(C), (D)

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