Complete guide to "Atoms and Molecules" for Chemistry students. Below you will find important questions and model answers to help you prepare.
We are building a dedicated quiz for this topic, but you can test your skills on a similar concept: The Fundamental Unit of Life - NCERT Class 9 Practice Set 1.
Which of the following correctly represents 360 g of water? (i) 2 moles of H₂0 (ii) 20 moles of water (iii) 6.022 × 10²³ molecules of water (iv) 1.2044×10²⁵ molecules of water
(i)
(i) and (iv)
(ii) and (iii)
(ii) and (iv)
Which of the following statements is not true about an atom?
Atoms are not able to exist independently
Atoms are the basic units from which molecules and ions are formed
Atoms are always neutral in nature
Atoms aggregate in large numbers to form the matter that we can see, feel or touch
The chemical symbol for nitrogen gas is
Ni
N₂
N⁺
N
The chemical symbol for sodium is
So
Sd
NA
Na
Which of the following would weigh the highest?
0.2 mole of sucrose (C₁₂ H₂₂ O₁₁)
2 moles of CO₂
2 moles of CaCO₃
10 moles of H₂O
Which of the following has maximum number of atoms?
18g of H₂O
18g of O₂
18g of CO₂
18g of CH₄
Which of the following contains maximum number of molecules?
1g CO₂
1g N₂
1g H₂
1g CH₄
3.42 g of sucrose are dissolved in 18g of water in a beaker. The number of oxygen atoms in the solution are
6.68 × 10²³
6.09 × 10²²
6.022 × 10²³
6.022 × 10²¹
A change in the physical state can be brought about
only when energy is given to the system
only when energy is taken out from the system
when energy is either given to, or taken out from the system
without any energy change
