1. Classify each of the following as a homogeneous or heterogeneous substance.

a. iron ore

b. quartz

c. granite

d. energy drink

e. oil-and-vinegar salad dressing

f. salt

g. rainwater

h. nitrogen

a. iron ore - heterogeneous substance

(it contains a mixture of iron oxides)

b. quartz - homogeneous substance

(it is the crystalline silicon dioxide SiO₂, which is a very pure form of SiO₂)

c. granite - heterogeneous substance

(it as mixture of different oxides, mainly aluminium and silicon oxides)

d. energy drink - heterogeneous substance

(a mixture of water, sugar, carbon dioxide and different substances that may boost concentration, like caffeine)

e. oil-and-vinegar salad dressing - heterogeneous substance

(this salad dressing of oil and vinegar is composed of unsaturated triglycerides, acetic acid and water)

f. salt - homogeneous substance

(sodium chloride NaCl)

g. rainwater - homogeneous substance

(assuming the the atmosphere is clean, it is just pure water H₂O)

h. nitrogen - homogeneous substance

(it is the main component of air and it is a diatomic molecule N₂)

A homogenous substance is one that has a uniform composition in all its parts.

A heterogenous substance has different composition in their parts.

a. iron ore

Iron ore is a heterogenous substance in which the composition of its part are not uniform.

b. quartz

Quartz is a homogenous substance because it is made up of silica alone joined in a framework pattern.

c. granite

Granite is heterogenous because it is an aggregate of several minerals like quartz, feldspars e. t. c

d. energy drink

Energy drink is homogenous due to the uniformity of the mixture.

e. oil-and-vinegar salad dressing

This is a heterogenous substance

f. salt

Salt is a homogenous substance because all its parts are uniform

g. rainwater

Rainwater is homogeous substance

h. nitrogen

Nitrogen is homogeous substance