Elements, Compounds, and Mixtures - Homework

First and Last Name

Answer explanation

The question asks for a person's full name, which includes both their first name and last name. Therefore, the correct response should provide both components clearly.

Email Address

Answer explanation

An email address is a unique identifier for an email account, typically formatted as '[e-mail]'. It allows users to send and receive messages electronically.

Class Period

Answer explanation

Class periods refer to the designated times during which classes are held in educational institutions. They structure the school day and help organize learning activities.

1. List three examples an element.

Answer explanation

Three examples of elements are Hydrogen (H), Oxygen (O), and Carbon (C). These are fundamental substances that cannot be broken down into simpler substances and are the building blocks of matter.

2. List three examples of a compound.

Answer explanation

Examples of compounds include water (H2O), carbon dioxide (CO2), and sodium chloride (NaCl). Each consists of two or more elements chemically bonded together, forming distinct substances with unique properties.

3. List three examples of a mixture.

Answer explanation

Examples of mixtures include salad (various vegetables), air (a mix of gases), and sand and salt (two solids combined). These mixtures retain their individual properties and can be separated physically.

4. A substance that is composed of two or more elements or compounds that are not chemically combined.

Answer explanation

The correct answer is a mixture. A substance made of two or more elements or compounds that are not chemically combined is known as a mixture, as opposed to a compound where elements are chemically bonded.

5. A compound that contains Carbon and at least one atom of Hydrogen, Oxygen, Phosphorus, Sulfur, or Nitrogen.

Answer explanation

The compound described must contain Carbon and at least one of the elements: Hydrogen, Oxygen, Phosphorus, Sulfur, or Nitrogen. This definition aligns with organic compounds, which are primarily based on Carbon.

6. A pure substance that is not able to be broken down chemically.

Answer explanation

The correct choice is an element, as it is a pure substance that cannot be broken down into simpler substances by chemical means. Elements are the fundamental building blocks of matter.

7. A substance that is composed of two or more different elements that are chemically combined in a set ratio.

Answer explanation

The description fits a compound, which is a substance made of two or more different elements chemically combined in a fixed ratio, such as water (H2O) or carbon dioxide (CO2).