English Medium कक्षा ९ - CBSE Question Bank Solutions for Science

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

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)

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?

On the basis of Thomson’s model of an atom, explain how the atom is neutral as a whole.

Rutherford’s ‘alpha (α) particles scattering experiment’ resulted in to discovery of

The number of electrons in an element X is 15 and the number of neutrons is 16. Which of the following is the correct representation of the element?

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

Which of the following statement is always correct?

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.

The book Systema Naturae was written by

Write true (T) or false (F)

Monera is divided into Archaebacteria and Eubacteria.