MCQ Questions for Class 9 Science Chapter 3 Atoms and Molecules
Solving the Atoms and Molecules Multiple Choice Questions of Class 9 Science Chapter 3 MCQ can be of extreme help as you will be aware of all the concepts. These MCQ Questions on Atoms and Molecules Class 9 with answers pave for a quick revision of the Chapter thereby helping you to enhance subject knowledge. Have a glance at the MCQ of Chapter 3 Science Class 9 and cross-check your answers during preparation.
Multiple Choice Questions
Question 1.
Who coined the term ‘Parmanu’ for the smallest indivisible particles?
(a) Leucippus
(b) L. Lavoisier
(c) Kanad
(d) None of them
Answer
Answer: (c) Kanad
Question 2.
The radius of a hydrogen atom is:
(a) 10-2
(b) 10-4
(c) 10-9
(d) 10-10
Answer
Answer: (d) 10-10
Question 3.
The most remarkable concept that Dalton’s atomic theory proposed was that of the:
(a) atomic weight
(b) atomic mass
(c) molar mass
(d) none of them
Answer
Answer: (b) atomic mass
Question 4.
The atomic mass of carbon is:
(a) 12
(b) 14
(c) 16
(d) 23
Answer
Answer: (a) 12
Question 5.
Compounds composed of metals and non-metals contain:
(a) non-charged species
(b) charged species
(c) both of them
(d) none of them
Answer
Answer: (b) charged species
Question 6.
The formula of ammonium sulphate is:
(a) NHSO4
(b) NH4SO2
(c) NHSO3
(d) (NH4)2SO4
Answer
Answer: (d) (NH4)2SO4
Question 7.
The word “mole” was introduced around 1896 by:
(a) Wilhelm Ostwald
(b) John Dalton
(c) Avogadro
(d) Vergilious
Answer
Answer: (a) Wilhem Ostwald
Question 8.
The chemical symbol for sodium is:
(a) So
(b) Sd
(c) NA
(d) Na
Answer
Answer: (d) Na
Question 9.
Which of the following has a maximum number of atoms?
(a) 18 g of H2O
(b) 18 g of O2
(c) 18 g of CO2
(d) 18 g of CH4
Answer
Answer: (d) 18 g of CH4
Question 10.
Which of the following contains a maximum number of molecules?
(a) 1g CO2
(b) 1g N2
(c) 1g H2
(d) 1g CH4
Answer
Answer: (c) 1g H2
Fill in the Blanks.
Question 11.
In a compound such as water, the ratio of the mass of hydrogen to the mass of oxygen is always ______
Answer
Answer: 1 : 8
Question 12.
Atomic radius is measured in ________
Answer
Answer: nanometre
Question 13.
The symbol of iron is Fe from its Latin name _________
Answer
Answer: Ferrum
Question 14.
One atomic mass unit is a mass unit equal to exactly ________ the mass of one atom of carbon-12.
Answer
Answer: \(\frac{1}{12}\)th
Question 15.
The formula unit mass of a substance is a sum of the atomic ______ of all its constituent atoms.
Answer
Answer: masses
Question 16.
Avogadro number is represented by ________
Answer
Answer: N0
Question 17.
The relative mass of atoms of all elements is obtained by comparing them with the mass of a _______ atom.
Answer
Answer: Carbon-12
Question 18.
The Avogadro constant 6.022 × 1023 is defined as the number of atoms in exactly ______ of carbon-12.
Answer
Answer: 12 g
True/False.
Question 19.
An atom is the smallest particle of the element that cannot usually exist independently and retains all its chemical properties.
Answer
Answer: True
Question 20.
The Law of conservation of mass states that mass can neither be created nor destroyed in a chemical reaction.
Answer
Answer: True
Question 21.
The mass of 1 mole of a substance is equal to its relative atomic or molecular mass in grams.
Answer
Answer: True
Question 22.
16u oxygen has 16 atoms of oxygen.
Answer
Answer: False
Question 23.
The atomic mass of calcium is 40.
Answer
Answer: True
Question 24.
Aluminium is diatomic.
Answer
Answer: False
Match the Column.
Question 25.
| A | B |
| 1. 1 mole of carbon atoms | (i) 1 g of H atoms |
| 2. 1 mole of molecules | (ii) Molecular mass in gram |
| 3. 1 mole of hydrogen atoms | (iii) Relative mass of those particles in gram |
| 4. 1 mole of any particle (atoms, molecules, ions) | (iv) 12-gram carbon atoms |
Answer
Answer:
| A | B |
| 1. 1 mole of carbon atoms | (iv) 12-gram carbon atoms |
| 2. 1 mole of molecules | (ii) Molecular mass in gram |
| 3. 1 mole of hydrogen atoms | (i) 1 g of H atoms |
| 4. 1 mole of any particle (atoms, molecules, ions) | (iii) Relative mass of those particles in gram |
Answer in one Word/Sentence.
Question 26.
What is the value of the Avogadro number?
Answer
Answer: 6.022 × 1023
Question 27.
How many atoms of hydrogen are there in 1g of hydrogen?
Answer
Answer: 6.022 × 1023
Question 28.
What name is given to a group of atoms carrying a charge?
Answer
Answer: Polyatomic ions
Question 29.
What term is given to the mass of one-mole atoms of a substance?
Answer
Answer: Molar mass
Question 30.
Write the chemical formula of calcium hydroxide.
Answer
Answer: Ca(OH)2
Question 31.
Write the chemical formula of sulphuric acid?
Answer
Answer: H2SO4
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