Classify each of the following as either heterogeneous or homogeneous mixture.

a. orange juice
b. tap water.
c. steel (a blend of iron and carbon)
d. air
e. raisin muffin

a homogeneous mixture cannot be separated into its parts without chemical reactions
a hetrogeneous mixture can be separated into its parts by simple methods such as filtration, physically picking out the parts, etc.

OJ = heterogeneous due to pulp, water and OJ
tap water = homogeneous
steel = homogeneous
air = heterogeneous, different gases
muffin = heterogeneous, pick out the raisins from the muffin