Question

For each of the following mixtures, state whether it is homogeneous or heterogeneous: (a) stainless steel (b) motor oil (c) soil (d) a tree

Short answer

Stainless steel: homogeneous; Motor oil: homogeneous; Soil: heterogeneous; Tree: heterogeneous.

Step-by-step solution

Understand the Definitions

A homogeneous mixture has a uniform composition throughout. A heterogeneous mixture has a non-uniform composition and distinct phases or parts can be seen.

Evaluate Stainless Steel

Stainless steel is an alloy, which means it is a homogeneous mixture of metals. The composition is the same throughout.

Evaluate Motor Oil

Motor oil is a homogeneous mixture of various hydrocarbons. It has a consistent composition throughout the solution.

Evaluate Soil

Soil is a heterogeneous mixture because it contains different substances like minerals, organic matter, air, and water which can be seen as distinct parts.

Evaluate a Tree

A tree is a heterogeneous mixture because it has different parts such as bark, leaves, wood, and branches which are not uniformly distributed.

Key concepts

mixture composition

Mixtures are classified based on their composition. This means we look at how the different substances in the mixture are distributed.

In a mixture, the components retain their own properties, unlike in a chemical compound where they form new substances. There are two primary types of mixtures: homogeneous and heterogeneous.

Understanding the composition is key to determining the type of mixture. Let's break it down further.

• Homogeneous Mixtures: These are uniform throughout, meaning the composition is consistent no matter where you sample it. This uniformity makes it hard to distinguish individual components.
• Heterogeneous Mixtures: These have a non-uniform composition, which means the different parts can be seen clearly. The distinct phases or parts can often be separated easily.

Recognizing the composition helps us categorize various substances accurately.

homogeneous mixtures

Homogeneous mixtures are uniform in their composition. This means if you take a sample from any part of the mixture, it will have the same ratio of components. These mixtures are also known as solutions.

Homogeneous mixtures can include:

• Stainless Steel: An alloy, which is a mixture of metals like iron, chromium, and nickel.
• Motor Oil: A blend of various hydrocarbons that form a consistent solution.
• Salt Water: Dissolved salt in water creates a uniform solution.

These mixtures do not show visible boundaries between their components. Additionally, they have only one phase – visibly and chemically consistent throughout. This uniformity often requires techniques like distillation to separate the components.

heterogeneous mixtures

Heterogeneous mixtures consist of visibly different substances or phases. The composition varies from one part of the mixture to another.

Examples of heterogeneous mixtures include:

• Soil: Contains minerals, organic matter, water, and air which can be distinctly identified.
• A Tree: Made up of various components like bark, leaves, wood, and branches.
• Fruit Salad: Different fruits mixed together but each piece retains its own distinct properties.

The different phases of a heterogeneous mixture can often be separated by physical means such as sorting, filtering, or using magnetic attraction. This separation is generally easier compared to homogeneous mixtures due to the visible distinctions between components.

examples of mixtures

Let's explore some common examples to better understand homogeneous and heterogeneous mixtures:

• Stainless Steel: A homogeneous mixture, or alloy, used in cutlery, construction, and appliances. The blend of metals is uniform throughout.
• Motor Oil: Another homogeneous mixture, used to lubricate engines. It consists of various hydrocarbons that create a consistent composition.
• Soil: A classic example of a heterogeneous mixture found in nature. It comprises different components like clay, sand, organic matter, and even living organisms.
• A Tree: An example of a heterogeneous mixture with distinct features. Bark, leaves, and branches all showcase the mixture's non-uniformity.

By studying these examples, it becomes clear how mixtures can be classified based on their uniformity and the ability to distinguish their components. This foundational understanding helps in many real-world applications, from cooking to industrial manufacturing.