Which of the following are chemical changes?
$(i)$ Decaying of wood
$(ii)$ Burning of wood
$(iii)$ Sawing of wood
$(iv)$ Hammering of a nail into a piece of wood

$(i)$ Name the compound formed on heating a mixture of iron filings and sulphur.
$(ii)$ If dilute $HCl$ is added to the above compound,name the gas evolved and write down its two properties.

An element is sonorous and highly ductile. Under which category would you classify this element? What other characteristics do you expect the element to possess?

State whether the following statement is true or false:
$A$ compound is a substance composed of two or more elements,chemically combined with one another in a fixed proportion.

Classify the following as chemical or physical changes:
$1$. Cutting of trees
$2$. Melting of butter in a pan
$3$. Rusting of almirah
$4$. Boiling of water to form steam
$5$. Passing of electric current through water and the water breaking down into hydrogen and oxygen gases
$6$. Dissolving common salt in water
$7$. Making a fruit salad with raw fruits
$8$. Burning of paper and wood

Classify the following into elements,compounds,and mixtures:
$(a)$ Sodium $(b)$ Soil $(c)$ Sugar solution $(d)$ Silver $(e)$ Calcium carbonate $(f)$ Tin
$(g)$ Silicon $(h)$ Coal $(i)$ Air $(j)$ Soap $(k)$ Methane $(l)$ Carbon dioxide $(m)$ Blood