$(a)$ Differentiate between a mixture and a compound.
$(b)$ You are provided with a mixture containing sand,iron filings,naphthalene,and sodium chloride. Describe the procedures you would use to separate these constituents from the mixture.

(N/A) Differences between a mixture and a compound:

Mixtures	Compounds
$(1)$ Elements or compounds just mix together to form a mixture.	$(1)$ Elements react to form a new substance called a compound.
$(2)$ Variable composition.	$(2)$ Composition is fixed.
$(3)$ Show the properties of its constituents.	$(3)$ Show the properties of the compound and not the constituent elements.
$(4)$ Constituents can be separated easily by physical methods.	$(4)$ Cannot be separated by physical methods.

$(b)$ Procedure to separate the mixture of sand,iron filings,naphthalene,and sodium chloride:
$(1)$ Use a magnet to move it over the mixture. The iron filings will be attracted to the magnet and can be separated.
$(2)$ The remaining mixture (sand,naphthalene,and sodium chloride) is heated. Naphthalene undergoes sublimation (changes directly from solid to gas) and can be collected separately.
$(3)$ Add water to the remaining mixture of sand and sodium chloride. Sodium chloride dissolves in water,while sand does not.
$(4)$ Filter the mixture. Sand remains as the residue on the filter paper,while sodium chloride solution passes through as the filtrate.
$(5)$ Finally,evaporate the filtrate (sodium chloride solution) to obtain solid sodium chloride.