Tissues — Science STD 9 — Question

State two characteristics of matter demonstrated by:
Diffusion.

Write the formula to find the magnitude of the gravitational force between the earth and an object on the surface of the earth.

A student placed a gas jar containing air in the upside down position over a gas jar full of red-brown bromine vapours. He observed that the red brown colour spread upwards into the jar containing air. Based on this observation, the student concluded that it is only the bromine vapour which moves up and diffuses into air in the upper jar, the air from the upper jar does not move down by diffusion into the lower jar containing bromine vapours. Do you agree with this conclusion of the student? Give reason for your answer.

20g silver nitrate solution is added to 20g of sodium chloride solution. What change in mass do you expect after the reaction and why?

Name the tissue which helps in easy bending of plants.

How is the impurity of iron present in several substances removed in industries?

The valencies (or charges) of some of the ions are given below:

Ion	Valency(Charges)	Ion	Valency(Charge)
Sodium ion	1+	Bromide ion	1-
Ammonium ion	1+	Hydroxide ion	1-
Calcium ion	2+	Sulphate ion	2-
Lead ion	2+	Phosphate ion	3-

Using this information, write down the formulate of the following compounds:

1. Sodium phosphate.
2. Ammonium sulphate.
3. Calcium hydroxide.
4. Lead bromide.

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

Give postulates of Dalton's atomic theory.