# Test Paper for Atoms and Molecules

Given below are the Class 9 Science CBSE Test Paper for Atoms and Molecules
a. Concepts questions
b. Calculation problems
c. Multiple choice questions
e. Fill in the blanks
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Question 1
State the law of mass conservation.

Question 2
What do you understand by the law of constant proportion?

Question 3
Who was responsible for coining the term atom?

Question 4
What is an atom?

Question 5
What is a molecule?

Question 6
What is atomicity?

Question 7
Define atomic mass unit.

Question 8.
Define ion.

Question 9
Provide a difference between cations and anions, along with an example for each.

Question 10

Question 11
(a)Explain how atoms exist.
(b)What do you understand by atomicity?
(c) Explain polyatomic ions.

Question 12
Explain atomic mass and gram atomic mass. Why does mass have different expressions viz, ‘u’ and ‘gm’?

Question 13
Define a mole. Give the importance of the mole.

Question 14
How many molecules are present in 1 ml of water?

Question 15.
Calculate the molecular mass of glucose, C6H12O6.

Question 16.
H2O is the formula for water. What information do you get from this formula?

Question 17
What is the formula unit mass of CaCl2and NaCl.
(Na = 23, Cl=35.5, Ca=40)

Question 18
(i) Name the body which approves the nomenclature of elements and compounds.
(ii) The symbol of sodium is written as Na and not as S. Give reason.
(iii) Name one element which form diatomic and one which form tetra atomic molecules.

Question 19
10.0 g CaCO3 on heating gave 4.4 g of CO2 and 5.6 g of CaO. Show that these observations are in agreement with law of conservation of mass.

Question 20
Why are Dalton's symbol not used in chemistry?

Question 21
What is the difference between2O, O2and O3.

Question 22
Find out
(1) the mass of a single oxygen atom
(2) the mass of a single oxygen molecule
(3) the mass of a mole of oxygen gas
(4) the mass of an oxygen ion
(5) the number of atoms in a mole of an oxygen molecule.

Question 23
What is the atomicity of oxygen and phosphorous?

Question 24
How many moles of $SO_2$ have same mass as 3 moles of oxygen?