English Medium कक्षा ९ - CBSE Question Bank Solutions for Science

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.

Chromosomes are made up of

Which cell organelle controls most of the activities of the cell?

The feature that is not a characteristic of protochordata?

Chemical nature of chitin is ______.

Which of the following are physical changes?

(i) Melting of iron metal

(ii) Rusting of iron

(iii) Bending of an iron rod

(iv) Drawing a wire of iron metal

Suggest separation technique(s) one would need to employ to separate the following mixture.

Mercury and water