Page 2 - 1.PRACTICE WORKSHEET

DIRECTION:Each of these questions contains an Assertion followed by Reason. Read them
carefully and answer the question on the basis of following options. You have to select the one
that best describes the two statements.
(a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
(c) If Assertion is correct but Reason is incorrect.

(d) If Assertion is incorrect but Reason is correct.
(e) If Assertion & Reason both are incorrect.
Q.5 Assertion : Atomicity of oxygen is 2.
Reason : 1 mole of an element contains 6.023 X1023 atoms.
Q.6Assertion : The molecular mass and formula unit mass of a substance is the sum
of atomic masses of all the atoms in the molecular formula or formula unit of a
compound.
Reason : The only difference between the molecular mass and formula unit mass is
that, former is for molecular compounds (covalent compounds) and latter is for ionic
compounds. However, their numerical value is the same.
Q.8 What are polyatomic ions? List two examples.
Q.9 Find the mass of 10 moles of sodium sulphite (Na2SO3).
(Na 23u ; S 32 u ; O 16u )
Q.10 Find the molecular mass of the following:
a) Sulphuric acid

b) Sodium hydroxide

c) Magnesium nitrate

( Mg= 24, H =1, S= 32, O= 16, Na=23, N= 14)