English Medium इयत्ता ९ - CBSE Question Bank Solutions

For the symbols H, D and T, write the subatomic particles (protons, neutrons and electrons) found in each one of them.

Which of the following statement is correct about the atom of an element ?

An ionic compound will be formed by the combination of one of the following pairs of elements. This pair of elements is :

Find the mass of 2 moles of nitrogen atoms.

How many atoms are there in exactly 12 g of carbon-12 element ? (C = 12 u)

Calculate the number of moles in 12.044 × 1025 atoms of phosphorus.

Which has more atoms, 50 g of aluminium or 50 g of iron ? Illustrate your answer with the help of calculations.

(Atomic masses : Al = 27 u ; Fe = 25 u)

A few drops of ‘Dettol’ when added to water the mixture turns turbid. Why?

What is the physical state of water at 0°C. 

What is the physical state of water at 250°C.

What is the physical state of water at 100ºC?

The chemical symbol for nitrogen gas is ______.

Which of the following has maximum number of atoms?

A change in the physical state can be brought about

Does the solubility of a substance change with temperature? Explain with the help of an example.

You are provided with a fine white coloured powder which is either sugar or salt. How would you identify it without tasting?

A sample of vitamic C is known to contain 2.58 ×10²⁴ oxygen atoms. How many moles of oxygen atoms are present in the sample?

Dalton’s atomic theory successfully explained

(i) Law of conservation of mass

(ii) Law of constant composition

(iii) Law of radioactivity

(iv) Law of multiple proportions

Atomic models have been improved over the years. Arrange the following atomic models in the order of their chronological order

1. Rutherford’s atomic model
2. Thomson’s atomic model
3. Bohr’s atomic model

Write any two observations which support the fact that atoms are divisible.