Class 9th Science Chapter – 3 Atoms and Molecules
| Textbook | NCERT |
| Class | 9th |
| Subject | Science |
| Chapter | 3rd |
| Chapter Name | Atoms and Molecules |
| Category | Class 9th Science |
| Medium | English |
| Source | Last Doubt |
| Class 9th Science Chapter – 3 Atoms and Molecules MCQ with answer were prepared based on the latest exam pattern. We have Provided Is Matter Around Us Class 9 Science MCQs Questions with Answers to help students understand the concept very well. |
Class 9th Science Chapter – 3 Atoms and Molecules
Chapter – 3
Is Matter Around Us Pure
MCQ
| (1) Which of the following correctly represents 360g of water? (i) 2 moles of water (ii) 20 moles of water (iii) 6.022 × 1023 molecules of water (iv) 1.2044 × 1025 molecules of water A. (i) B. (i) and (iv) C. (ii) and (iii) D. (ii) and (iv) Answer – (D) (ii) and (iv) |
| (2) Which of the following statements is not true about an atom? A. Atoms are not able to exist independently. B. Atoms are the basic units from which molecules and ions are formed. C. Atoms are always neutral in nature. D. Atoms aggregate in large numbers to form the matter that we can see, feel or touch. Answer – (D) Atoms aggregate in large numbers to form the matter that we can see, feel or touch. |
| (3) An element X is divalent and another element Y is tetravalent. The compound formed by these two elements will be? A. XY B. XY2 C. X2Y D. XY4 Answer – (B) XY2 |
| (4) 3.42 g of sucrose are dissolved in 18 g of water in a beaker. The numbers of oxygen atoms in the solution are? A. 6.68 ×1023 B. 6.09 ×1022 C. 6.022 ×1023 D. 6.022 ×1021 Answer – (A) 6.68 × 1023 |
| (5) A change in the physical state can be brought about? A. Only when energy is given to the system B. Only when energy is taken out from the system C. When energy is either given to, or taken out from the system D. Without any energy change Answer – (C) When energy is either given to, or taken out from the system |
| (6) A sample of NH3 molecule irrespective of source contains 82.35% Nitrogen and 17.65% of Hydrogen by mass. This data supports? A. Law of Conservation of Mass B. Las of Multiple Proportions C. Law of Definite Proportions D. Avogadro’s Law Answer – (C) Law of Definite Proportions |
| (7) Molecular mass is defined as the? A. Mass of one molecule of any substance compared with the mass of one atom of C – 12 B. Mass of one atom compared with the mass of one atom of hydrogen C. Mass of one atom compared with the mass of one molecule D. None of the above Answer – (A) Mass of one molecule of any substance compared with the mass of one atom of C – 12 |
| (8) An element X is divalent and another element Y is tetravalent. The compound formed by these two elements will be? A. XY B. XY2 C. X2Y D. XY4 Answer – (B) XY2 |
| (9) 1 u or 1 amu means? A. 1/12th mass of C-12 atoms B. Mass of C-12 atom C. Mass of O-16 atom D. Mass of Hydrogen molecule Answer – (A) 1/12th mass of C-12 atoms |
| (10) Which of the following contains maximum number of molecules? A. 19 CO2 B. 1 g N2 C. 1 g H2 D. 1 g CH4 Answer – (C) 1 g H2 |
| (11) The molecular formula of potassium nitrate is ________? A. KNO3 B. KNO C. KNO2 D. KON Answer – (A) KNO3 |
| (12) The atomic mass of sodium is 23. The number of moles in 46g of sodium is ________? A. 4 B. 2 C. 0 D. ½ Answer – (B) 2 |
| (13) How many atoms of oxygen are present in 300 grams of CaCO3? A. 54.207 × 1023 B. 6.207 × 1023 C. 12.207 × 1023 D. 22.2 × 1023 Answer – (A) 54.207 × 1023 |
| (14) Which of the following represents a correct chemical formula? A. CaCl B. BiPO4 C. NaSO4 D. NaS Answer – (B) BiPO4 |
| (15) What is the formula mass unit of ZnO? A. 18 u B. 81 u C. 88 u D. 188 u Answer – (B) 81 u |
| (16) Which of the following represents the correct relation between Avogadro’s number (No), number of particles (N) and moles (n)? A. N = N / No B. N = No / N C. N = N No D. All are correct Answer – (A) n = N / No |
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