Classify the following as physical or chemical properties:
$(a)$ The composition of a sample of steel is: $98\%$ iron,$1.5\%$ carbon,and $0.5\%$ other elements.
$(b)$ Zinc dissolves in hydrochloric acid with the evolution of hydrogen gas.
$(c)$ Metallic sodium is soft enough to be cut with a knife.
$(d)$ Most metal oxides form alkalis on interacting with water.

$(a)$ Write any three points of differences between homogeneous and heterogeneous mixtures.
$(b)$ Give two reasons for supporting that water is a compound and not a mixture.

Suggest a suitable separation technique for the following:
$(i)$ Mercury and water.
$(ii)$ Coloured components from blue ink.
$(iii)$ Ammonium chloride and potassium chloride.
$(iv)$ Mixture of alcohol and water.

What happens when a hot saturated solution is cooled?

Identify which of the following are elements,mixtures,or compounds:
$(i)$ Brass $(ii)$ Diamond $(iii)$ Sand.

Fill in the blanks:
$(a)$ $A$ colloid is a .......... mixture and its components can be separated by the technique known as .........
$(b)$ Ice,water,and water vapour look different and display different ......... properties but they are ......... the same.
$(c)$ $A$ mixture of chloroform and water taken in a separating funnel is mixed and left undisturbed for some time. The upper layer in the separating funnel will be of ......... and the lower layer will be that of .........
$(d)$ $A$ mixture of two or more miscible liquids,for which the difference in the boiling points is less than $25 \, K$,can be separated by the process called .........
$(e)$ When light is passed through water containing a few drops of milk,it shows a bluish tinge. This is due to the ......... of light by milk and the phenomenon is called ......... . This indicates that milk is a ......... solution.