Practice Worksheet
CBSE Class 9 Science
Topic: Atoms and Molecules
Very Short Answer
Q1) What is the law of conservation of mass? Write the formula of a polyatomic cation.
Ans: When a physical or chemical change occurs the total mass of the reactants is equal to the total mass of the products formed in the reaction.
NH4+
Q2) Suraj was given a fine white-colored powder which is either sugar or salt. How would he identify it without tasting?
Ans: On heating, white coloured powder, it will char if it is sugar. On the other hand, the powder may be dissolved in water and pass an electric current through it. If it conducts,
it is salt.
Q3) What is unified atomic mass unit (u)?
Ans: Unified atomic mass unit is equal to 1/12th the mass of a carbon-12 atom.
Q4) How many mole atoms of oxygen (O) are present in 96g of ozone?
Ans:
Q5) Name the ions present in NH4NO3
Ans: NH4+ and NO3-
Click below to download practice worksheet for CBSE Class 9 Science Atoms and Molecules Worksheet Set D