Which of the following are homogeneous in nature?

$(a)$ $7\, g$ of iron filings and $4\, g$ of sulphur powder is treated with dilute sulphuric acid at room temperature. Name the gas produced.
$(b)$ The same mixture is heated strongly,cooled and then treated with dilute sulphuric acid. Which gas would be produced?
$(c)$ What is the cause of this difference in results of chemical reaction in different conditions?

State whether the following statement is true or false:
Metals are malleable,ductile,sonorous,and lustrous.

$(a)$ Illustrate with an example that physical and chemical changes can take place together.
$(b)$ Which of the following are chemical changes?
$(i)$ Mixing of iron filings and sand
$(ii)$ Growth of plant
$(iii)$ Rusting of iron
$(iv)$ Freezing of water

Non-metals are usually poor conductors of heat and electricity. They are non-lustrous,non-sonorous,non-malleable,and are coloured.
$(a)$ Name a lustrous non-metal.
$(b)$ Name a non-metal which exists as a liquid at room temperature.
$(c)$ The allotropic form of a non-metal is a good conductor of electricity. Name the allotrope.
$(d)$ Name a non-metal which is known to form the largest number of compounds.
$(e)$ Name a non-metal other than carbon which shows allotropy.
$(f)$ Name a non-metal which is required for combustion.

$(a)$ Compare metals and non-metals based on their physical properties. (any four points)
$(b)$ What are metalloids? Give two examples.
$(c)$ Identify metals from the following: Boron,sodium,mercury,carbon.