Is Matter Around Us Pure — Science STD 9 — Question

Why are gases so easily compressible whereas it is almost impossible to compress a solid or a liquid?

What is the major factor which determines the state of matter?

For the symbol H,D and T tabulate three sub-atomic particles found in each of them.

Which of the following are chemical changes and which physical? Give reason.

1. A glass bottle breaking.
2. Coal burning in air.
3. Making a cake.
4. Wool being knitted into a sweater.

Define the atomic mass unit.

An element has Z = 7. What is the valency of the element? Also name the element.

The atomic species A and B have different number of protons but the same number of nucleons. On the other hand, the atomic species X and Y have the same number of protons but different number of nucleons. Which pair is an example of isobars? Why?

‘If 100 grams of calcium carbonate (whether in the form of marble or chalk) are decomposed completely, then 56 grams of calcium oxide and 44 grams of carbon dioxide are obtained’. Which law of chemical combination is illustrated by this statement?

Why does water have higher boiling point than alcohol? At what temperature in Kelvin, it can be changed into solid state and into vapours?

Classify the following into true solutions and colloidal solutions:
Ink, Salt solution, Starch solution, Blood, Sugar solution.