Identify the following substances as pure substances, elements, compounds, mixtures,

or solutions (answers may include more than one classification): mud, copper, salt
water, carbon monoxide

I'm not a science teacher -- and remember very little from my science classes 65 years ago.

I suggest you google each of those.

copper. Element. Pure substance.

salt. I assume you mean table salt but there are many salts. It is pure if it is 100% salt, NaCl. It is a compound.
Water is a compound. It is a pure substance.
Carbon monoxide is a compound and a pure substance.
Mud is a mixture. Some parts of the mud are in solution.
The word "pure" can be a little misleading. I consider something as pure if it is 100%; table salt is pure in my opinion if it is 100% salt but it isn't pure in the sense that it is partly sodium and partly chlorine. However, it IS a pure substance in that there is nothing mixed with it. By the way, most table salt one buys at the store has been "iodized" which makes it a mixture. One CAN buy un-iodized salt and that is a pure compound.

Mud: Mixture

Copper: Element
Saltwater: Solution (mixture of water and salt)
Carbon monoxide: Compound

To identify the substances, we need to understand the definitions of pure substances, elements, compounds, mixtures, and solutions:

1. Pure Substances: These are substances that are made up of only one type of particle (either atoms or molecules) and have a fixed composition. Pure substances cannot be separated into simpler substances by physical means.

2. Elements: These are pure substances that cannot be broken down into simpler substances by chemical means. They consist of only one type of atom.

3. Compounds: These are pure substances made up of two or more different types of atoms chemically combined in a fixed ratio. Compounds can be broken down into simpler substances through chemical reactions.

4. Mixtures: These are the combination of two or more substances that are physically mixed together. Mixtures have variable composition and can be separated using physical means.

5. Solutions: These are homogeneous mixtures where one substance (called solute) is uniformly distributed in another substance (called solvent), forming a single phase.

Now, let's identify the substances you provided:

1. Mud: Mud is a mixture. It consists of a combination of soil, water, and various organic and inorganic materials. Mud can be separated by physical means, such as filtering or settling.

2. Copper: Copper is an element. It is a pure substance made up of only one type of atom, which is copper itself.

3. Saltwater: Saltwater is a solution. It is a homogeneous mixture where salt (solute) is dissolved in water (solvent). It forms a single phase and cannot be easily separated into its components.

4. Carbon monoxide: Carbon monoxide is a compound. It is a pure substance made up of two different atoms (carbon and oxygen) chemically bonded together in a fixed ratio.

So, the classification of the substances you provided is as follows:
- Mud: Mixture
- Copper: Element
- Saltwater: Solution
- Carbon monoxide: Compound