Saturday, 20 February 2021

CBSE Class 9 Science - MCQ and Online Tests - Chemistry - Unit 3 - Atoms and Molecules

CBSE Class 9 Science – MCQ and Online Tests – Chemistry – Unit 3 – Atoms and Molecules

Every year CBSE  schools conducts Annual Assessment exams for 6,7,8,9,11th standards. These exams are very competitive to all the students. So our website provides online tests for all the 6,7,8,9,11th standard’s subjects. These tests are also very effective and useful for those who preparing for any competitive exams like Olympiad etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.

These online tests are based on latest CBSE syllabus. While attempting these our students can identify the weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly. 


 

CBSE Class 9 Science – MCQ and Online Tests – Chemistry – Unit 3 – Atoms and Molecules

Question 1.
Which of the following has maximum number of atom?
(a) 18 g H2O
(b) 18 g of O2
(c) 18 g of CO2
(d) 18 g of CH4

Answer

Answer: (d) 18 g of CH4


Question 2.
Which of the following has maximum number of atoms?
(a) 18 g of H2O
(b) 18 g of O2
(c) 18 g of CO2
(d) 18 g of CO4

Answer

Answer: (d) 18 g of CO4


Question 3.
Which of the following correctly represents 360 g of water?
(i) 2 moles of H2O
(ii) 20 moles of water
(iii) 6.022 × 1023 molecules of water
(iv) 1.2044 × 1025 molecules of water
(a) (i)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (ii) and (iv)

Answer

Answer: (d) (ii) and (iv)


Question 4.
Which of the following represents 12 u?
(a) Mass of 1 hydrogen atom
(b) Mass of C-12 atom
(c) Mass of 0-16 atom
(d) 1/12th of mass of C-12 atom.

Answer

Answer: (d) 1/12th of mass of C-12 atom.


Question 5.
Which of the following would weigh the highest?
(a) 0.2 mole of sucrose (C12H22O11)
(b) 2 moles of CO2
(c) 2 moles of CaCO3
(d) 10 moles of H2O

Answer

Answer: (c) 2 moles of CaCO3


Question 6.
3.42 g of sucrose are dissolved in 18 g of water in a beaker. The number of oxygen atoms in the solution are
(a) 6.68 × 1023
(b) 6.09 × 1022
(c) 6.022 × 1023
(d) 6.022 × 102321

Answer

Answer: (a) 6.68 × 1023


Question 7.
Which of the following would weigh the highest?
(a) 0.2 mole of sucrose (C12H22O11)
(b) 2 moles of CO2
(c) 2 moles of CaCO3
(d) 10 moles of H2O

Answer

Answer: (c) 2 moles of CaCO3


Question 8.
A change in the physical state can be brought about
(a) only when energy is given to the system
(b) only when energy is taken out from the system
(c) when energy is either given to, or taken out from the system
(d) without any energy change

Answer

Answer: (c) when energy is either given to, or taken out from the system


Question 9.
The relative molecular mass of Na2S2O3.5H2O is
(a) 250 amu
(b) 250 g
(c) 248 amu
(d) 248 g

Answer

Answer: (c) 248 amu


Question 10.
Percentage of calcium in calcium carbonate is
(a) 40
(b) 30
(c) 48
(d) 36

Answer

Answer: (a) 40


Question 11.
Which has maximum number of molecules?
(a) 1 g of CO2
(b) 1 g of N2
(c) 1 g of H2
(d 1 g of CH4

Answer

Answer: (c) 1 g of H2


Question 12.
What mass of carbon dioxide (CO2) will contain 3.011 × 1023 molecules?
(a) 11.0 g
(b) 22.0 g
(c) 4.4 g
(d) 44.0 g

Answer

Answer: (b) 22.0 g


Question 13.
The value of Avogadro’s constant is:
(a) 6.0 × 1024
(b) 6.01 × 1022
(c) 6.022 × 1023
(d) 6.022 × 10-23

Answer

Answer: (c) 6.022 × 1023


Question 14.
How many times an atom of sulphur is heavier than an atom of carbon?
(a) 32 times
(b) 12 times
(c) 8/3 times
(d) 12/32 times

Answer

Answer: (c) 8/3 times


Question 15.
The number of oxygen atoms in 4.4 g of CO2 is approx.
(a) 6 × 1022
(b) 6
(c) 12 × 1023
(d) 1.2 × 1023

Answer

Answer: (d) 1.2 × 1023


 

 

 

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