English Medium Class 9 - CBSE Question Bank Solutions for Science

Which postulate of Dalton’s atomic theory can explain the law of constant proportions ?

The particle not present in an ordinary hydrogen atom is :

The atomic theory of matter was proposed by :

Which of the following statement is always correct?

The law of constant proportions was given by :

In water, the proportion of oxygen and hydrogen by mass is :

In an experiment, 4.90 g of copper oxide was obtained from 3.92 g of copper. In another experiment, 4.55 g of copper oxide gave, on reduction, 3.64 g of copper. Show with the help of calculations that these figures verify the law of constant proportions.

When 5 g of calcium is burnt in 2 g of oxygen, then 7 g of calcium oxide is produced. What mass of calcium oxide will be produced when 5 g of calcium is burnt in 20 g of oxygen ? Which law of chemical combination will govern your answer ?

What do we call those particles which have more or less electrons than the normal atoms ?

What do we call those particles which have more electrons than the normal atoms ?

What do we call those particles which have less electrons than the normal atoms ?

What do we call those particles which are formed by the gain of electrons by atoms ?

What do we call those particles which are formed by the loss of electrons by atoms ?

Work out the formulae for the following compounds :

Sodium oxide

Work out the formulae for the following compounds:

Calcium carbonate

What is the physical state of water at 25°C. 

Find out incorrect sentence

Girth of stem increases due to

Which cell does not have perforated cell wall?

A person met with an accident in which two long bones of hand were dislocated. Which among the following may be the possible reason?