R4RIN – MCQs, Mock Tests | NCERT Class 9 Class 9 Science Chapter 3 Atoms and Molecules

The chemical symbol for nitrogen gas is

1. Ni
2. N2
3. N+
4. N

✅ Correct Answer: 2

The chemical symbol for sodium is

1. So
2. Sd
3. NA
4. Na

✅ Correct Answer: 4

Which of the following would weigh the highest?

1. 0.2 mole of sucrose (C12H22O11)
2. 2 moles of CO2
3. 2 moles of CaCO3
4. 10 moles of H2O

✅ Correct Answer: 3

Which of the following has maximum number of atoms?

1. 18 g of H2O
2. 18 g of O2
3. 18 g of CO2
4. 18 g of CO4

✅ Correct Answer: 4

Which of the following correctly represents 360 g of water? (i) 2 moles of H2O (ii) 20 moles of water (iii) 6.022 × 1023 molecules of water (iv) 1.2044 × 1025 molecules of water

1. (i)
2. (i) and (iv)
3. (ii) and (iii)
4. (ii) and (iv)

✅ Correct Answer: 4

3.42 g of sucrose are dissolved in 18 g of water in a beaker. The number of oxygen atoms in the solution are

1. 6.68 × 1023
2. 6.09 × 1022
3. 6.022 × 1023
4. 6.022 × 102321

✅ Correct Answer: 1

A change in the physical state can be brought about

1. only when energy is given to the system
2. only when energy is taken out from the system
3. when energy is either given to, or taken out from the system
4. without any energy change

✅ Correct Answer: 3

The relative molecular mass of Na2S2O3.5H2O is

1. 250 amu
2. 250 g
3. 248 amu
4. 248 g

✅ Correct Answer: 3

Which of the following has maximum number of atom?

1. 18 g H2O
2. 18 g of O2
3. 18 g of CO2
4. 18 g of CH4

✅ Correct Answer: 4

Percentage of calcium in calcium carbonate is

1. 40
2. 30
3. 48
4. 36

✅ Correct Answer: 1

Which has maximum number of molecules?

1. 1 g of CO2
2. 1 g of N2
3. 1 g of H2
4. 1 g of CH4

✅ Correct Answer: 3

What mass of carbon dioxide (CO2) will contain 3.011 × 1023 molecules?

1. 11.0 g
2. 22.0 g
3. 4.4 g
4. 44.0 g

✅ Correct Answer: 2

The value of Avogadro’s constant is:

1. 6.0 × 1024
2. 6.01 × 1022
3. 6.022 × 1023
4. 6.022 × 10-23

✅ Correct Answer: 3

How many times an atom of sulphur is heavier than an atom of carbon?

1. 32 times
2. 12 times
3. 8/3 times
4. 12/32 times

✅ Correct Answer: 3

The number of oxygen atoms in 4.4 g of CO2 is approx.

1. 6 × 1022
2. 6
3. 12 × 1023
4. 1.2 × 1023

✅ Correct Answer: 4

Which of the following represents 12 u?

1. Mass of 1 hydrogen atom
2. Mass of C-12 atom
3. Mass of 0-16 atom
4. 1/12th of mass of C-12 atom.

✅ Correct Answer: 4

The molecule having an atomicity of 4 is:

1. Sulphate molecule
2. Ozone molecule
3. Phosphorus molecule
4. Methane molecule

✅ Correct Answer: 3