Question

Classify each of the following as an element, a compound, or a mixture: a. carbon in pencils b. carbon dioxide \(\left(\mathrm{CO}_{2}\right)\) we exhale c. orange juice d. neon gas in lights e. salad dressing of oil and vinegar

Short answer

a. Element, b. Compound, c. Mixture, d. Element, e. Mixture

Step-by-step solution

- Understanding Elements

An element is a pure substance that cannot be broken down into simpler substances by chemical means. Examples include carbon and neon.

- Understanding Compounds

A compound is a substance formed when two or more chemical elements are chemically bonded together. Examples include carbon dioxide \(\text{CO}_2\).

- Understanding Mixtures

A mixture is a combination of two or more substances that are not chemically bonded. Examples include orange juice and salad dressing.

- Classify Carbon in Pencils

Carbon found in pencils is an example of an element because it is a pure form of carbon.

- Classify Carbon Dioxide

Carbon dioxide \(\text{CO}_2\) we exhale is a compound because it consists of carbon and oxygen atoms that are chemically bonded.

- Classify Orange Juice

Orange juice is a mixture because it contains various substances such as water, sugar, vitamins, and other compounds that are not chemically bonded.

- Classify Neon Gas

Neon gas in lights is an element because it is a pure substance consisting entirely of neon atoms.

- Classify Salad Dressing

Salad dressing of oil and vinegar is a mixture because it contains oil and vinegar, which do not chemically bond and can be physically separated.

Key concepts

Elements

Elements are the simplest form of matter. They consist of only one kind of atom and cannot be broken down into simpler substances by chemical reactions. All elements are listed on the Periodic Table.

Examples of elements include:

• Carbon (C) - used in pencils.
• Neon (Ne) - used in lights.

Elements are pure substances and are the building blocks for all other substances.

Compounds

Compounds are substances formed when two or more elements are chemically bonded together. The properties of a compound are different from the properties of the elements that make it up.

For example:

• Carbon Dioxide \(CO_2\) - composed of carbon and oxygen atoms, which are bonded together.

In a chemical reaction, compounds can be broken down into their individual elements. Unlike mixtures, compounds have a definite composition.

Mixtures

Mixtures are made up of two or more substances that are physically combined, not chemically bonded. Each substance in a mixture retains its individual properties and can be separated by physical means.

Examples of mixtures include:

• Orange Juice - contains water, sugar, vitamins, and other compounds.
• Salad Dressing - a combination of oil and vinegar.

Mixtures can be either homogeneous (uniform composition) or heterogeneous (non-uniform composition).

Pure Substances

Pure substances have a uniform and definite composition. They can be either elements or compounds.

Pure substances have distinct physical and chemical properties. Examples include:

• Elements like Carbon and Neon.
• Compounds like Water \(H_2O\) and Carbon Dioxide \(CO_2\).

Unlike mixtures, pure substances cannot be separated into other substances by physical methods.