9th Class Science: Is Matter Around Us Pure

Question: Name one metal and one none-metal which exist as liquids at room temperature.

Answer: Mercury and Bromine

Question: Name a metal which is soft and non-metal which is hard?

Answer: Sodium and diamond

Question: Name a non-metal which is a good conductor of electricity.

Answer: Graphite

Question: Name a liquid which can be classifieds a pure substance and conducts electricity.

Answer: Mercury.

Question: Name a solid, a liquid and a gaseous non-metal.

Answer: Carbon, bromine and Hydrogen

Question: Which allows metals to be hammered in then sheets?

Answer: Malleability

Question: Which enable metals to be drawn into wires?

Answer: Debility

Question: What is meant by saying that metals are malleable and ductile?

Answer: This means that metals can be hammered into thin sheets as well as drawn into thin a hammer.

Question: What is mean by saying that metals are sonorous?

Answer: This means that metal produce a ringing sound when struck

Question: What is meant by saying that metals are lustrous?

Answer: This means that has a shining surface.

Question: What are pure substances? Give eg of pure substances.

Answer: A substance which is made up of only one kind of particles is known as a pure substances. For Eg: Sugar and iron.

Question: State 3 reasons why you think air is a mixture and water is a compound.

Answer: They are:

1. Water is made by the chemical bonding of Hydrogen and oxygen particles where as air is a simple mixture of diffused gases.
2. The ratio of H and O2 in water is 2:1 where as in air there is no specific ration of its constituent gases.
3. Water is made up of similar group of molecules where  as the air have different concentration of different places.

Question: Name two solid, 2 liquid, 2 gaseous elements at room temperature.

Answer: Liquid = Bromine and mercury

Gas = Hydrogen, Nitrogen

Solid = Carbon, Sulfur

Question: Compare the properties of metal and non-metal on the basis of malleability ductility and electrical conductivity.

Answer: