Molecular and Formula MassPractice Questions & MCQs
Practice Molecular and Formula Mass questions from Atoms and Molecules (Class 9 Science) - important MCQs with answers and step-by-step solutions. Solve the sample questions below, then practice the full set free on the RankByte app.
Molecular and Formula MassQuiz - Solve & Score
Q1. One mole of any substance contains how many particles?
- A.6.022 x 10^23 (Avogadro's number)
- B.1000
- C.6.022 x 10^-23
- D.12
Answer: A. 6.022 x 10^23 (Avogadro's number)
NCERT fact (chemistry, chapter 'Atomic Foundations of Matter'): Number of moles n = given mass / molar mass; compute the molar mass by summing atomic masses, then n = m / M => substituting the data yields the quoted result; hence the answer = 6.022 x 10^23 (Avogadro's number). Why option A fits - Correct. Distractor analysis: option B) '1000' is incorrect: A mole is 6.022 x 10^23 particles, not 1000; option C) '6.022 x 10^-23' is incorrect: Avogadro's number is 6.022 x 10^23, a large number (positive exponent). Final answer - A) 6.022 x 10^23 (Avogadro's number).
Q2. Why do we use 'formula unit mass' for NaCl instead of 'molecular mass'?
- A.NaCl exists as a giant ionic lattice, not separate molecules
- B.NaCl is a gas of separate molecules
- C.NaCl has no mass
- D.sodium and chlorine are not elements
Answer: A. NaCl exists as a giant ionic lattice, not separate molecules
Q3. The molecular mass of a substance is the:
- A.sum of the atomic masses of all atoms in one molecule
- B.mass of one atom only
- C.number of molecules in a sample
- D.mass of the container
Answer: A. sum of the atomic masses of all atoms in one molecule
Master Molecular and Formula Mass on RankByte
Step-by-step solutions, mock tests, live ranks and streaks - free to start.
Get early accessMolecular and Formula Mass - Frequently asked questions
Where can I practise Molecular and Formula Mass questions for Class 9 Science?
RankByte has Molecular and Formula Mass practice questions and MCQs from Atoms and Molecules (Class 9 Science), each with the correct answer and a step-by-step solution - free to start.
Are these Molecular and Formula Mass questions important for the exam?
Yes. These Molecular and Formula Mass important questions follow the Science exam pattern (CBSE Boards, plus JEE and NEET foundation), so they help with both school and competitive prep.
Do the Molecular and Formula Mass questions come with answers and solutions?
Every Molecular and Formula Mass question on RankByte comes with the correct answer and a full step-by-step solution, so you learn the concept instead of just guessing.