Question

Classify each of the following mixtures as homogeneous or heterogeneous: a. nonfat milk b. chocolate-chip ice cream c. gasoline d. peanut-butter-and-jelly sandwich e. cranberry juice

Short answer

a. homogeneous, b. heterogeneous, c. homogeneous, d. heterogeneous, e. homogeneous

Step-by-step solution

Identifying Nonfat Milk

Nonfat milk is uniform in composition and appears the same throughout. Therefore, it is classified as a homogeneous mixture.

Identifying Chocolate-Chip Ice Cream

Chocolate-chip ice cream contains distinct particles, such as chocolate chips, mixed unevenly in the ice cream. Thus, it is classified as a heterogeneous mixture.

Identifying Gasoline

Gasoline is a uniform liquid solution where the different hydrocarbons are mixed uniformly. Hence, it is classified as a homogeneous mixture.

Identifying Peanut-Butter-And-Jelly Sandwich

A peanut-butter-and-jelly sandwich has different ingredients (bread, peanut butter, jelly) that are not mixed uniformly. Therefore, it is classified as a heterogeneous mixture.

Identifying Cranberry Juice

Cranberry juice, assuming it is well-mixed and consistent in composition, is a homogeneous mixture.

Key concepts

mixture classification

Mixtures come in two primary types: homogeneous and heterogeneous.
A homogeneous mixture is uniform throughout, meaning its composition is consistent.
Examples include nonfat milk and gasoline.
Conversely, a heterogeneous mixture has a non-uniform composition. It contains distinct parts or phases, each with different properties.
Chocolate-chip ice cream and a peanut-butter-and-jelly sandwich are examples of heterogeneous mixtures.
Recognizing these differences is crucial in chemistry for identifying material properties and behaviors.

uniform composition

When we say a mixture has a uniform composition, we mean it looks the same throughout.
In a homogeneous mixture, the particles are evenly distributed. You can't easily separate the components physically.
For instance:

• Nonfat milk appears smooth and the same in every part of the glass.
• Gasoline is a liquid you can't tell has multiple hydrocarbons just by looking.

Having a uniform composition makes these mixtures quite stable and predictable in properties.

non-uniform composition

A non-uniform composition indicates that the mixture contains regions with different properties.
These are heterogeneous mixtures. You can often see or separate the different parts.
Common examples include:

• Chocolate-chip ice cream, where chocolate chips are not evenly spread throughout the ice cream base.
• A peanut-butter-and-jelly sandwich, which has clear, separate layers of bread, peanut butter, and jelly.

These mixtures vary in texture, appearance, and sometimes even taste within the same sample.

solution

A solution is a special type of homogeneous mixture.
It consists of a solute dissolved in a solvent.
Solutions have a uniform composition and appearance.
For example:

• Gasoline is a solution of various hydrocarbons mixed uniformly to form a clear liquid.
• Cranberry juice, when well-mixed, is also a solution where the juice's components are evenly distributed.

Solutions can be solid, liquid, or gas, and they play a crucial role in many chemical processes and everyday life.