Understanding Elements, Compounds, and Mixtures

Why are elements and compounds considered pure substances?

• They are made of only one type of atom or molecule.

• They can be easily separated into simpler substances.

• They are always found in nature.

• They have varying chemical properties.

What makes table salt a compound?

• It is made of a single type of atom.

• It cannot be split into simpler substances.

• It is composed of sodium and chlorine atoms.

• It is a natural element.

Which of the following is an example of an element?

• Table salt

• Sugar

• Water

• Iron

How are elements represented in the periodic table?

• By their chemical formula

• By their atomic number

• By their mass number

• By a unique symbol

What is the basic unit of an element?

• Mixture

• Compound

• Atom

• Molecule

What defines a compound?

• A physical combination of substances

• A single type of atom

• A mixture of elements

• A pure substance with a fixed ratio of elements

What happens if the ratio of elements in a compound changes?

• The compound becomes an element.

• The compound remains the same.

• The compound becomes a mixture.

• A new compound is formed.

How are mixtures different from compounds?

• Mixtures are pure substances.

• Mixtures are chemically combined.

• Mixtures have a fixed ratio of components.

• Mixtures are physically combined.

Which of the following is an example of a mixture?

• Water

• Table salt

• Gold

• Salad

Why are mixtures considered impure substances?

• They cannot be separated into simpler substances.

• They consist of physically combined substances.

• They have uniform chemical properties.

• They contain only one type of molecule.