9.1 Composition of Matter

Review of Types of Matter

A pure substance has a constant, defined composition and cannot be separated into simpler substances by physical means. There are two types of pure substances, elements and compounds.

Elements are pure substances that are made of only one type of atom. The periodic table is a table containing all elements.

Compounds are pure substances that are made of more than one type of atom, and can be decomposed or broken down into its elements by chemical means.

A mixture is composed of more than one element and / or compound. Different mixtures of the same substances can have different compositions (i.e., a mixture of water and sodium chloride may be 80% water and 20% sodium chloride, or 20% water and 80% sodium chloride.) There are two types of mixtures, homogeneous and heterogeneous.

A homogeneous mixture has the same composition of elements and / or compounds throughout. If you observed a homogeneous mixture under a microscope, you would see that the particles of various components are evenly distributed. A homogeneous mixture is also called a solution.

A heterogeneous mixture has different regions or areas with different compositions and properties. The substances in a heterogeneous mixtures are not evenly distributed.

Is mercury an element, compound, or mixture?

• Element

• Compound

• Mixture

Is table salt, sodium chloride, an element, compound, or mixture?

• Element

• Compound

• Mixture

Is (pure) water an element or compound?

• Element

• Compound

• Mixture

What type of mixture is coffee?

• Element

• Compound

• Homogeneous Mixture

• Heterogeneous Mixture

What type of mixture is household vinegar?

• Element

• Compound

• Homogeneous Mixture

• Heterogeneous Mixture

What type of mixture is air?

• Element

• Compound

• Homogeneous Mixture

• Heterogeneous Mixture

Tap water is a(n)

• Element

• Compound

• Homogeneous Mixture

• Heterogeneous Mixture

Fourteen carat gold is a(n)

• Element

• Compound

• Homogeneous Mixture

• Heterogeneous Mixture

Carbon dioxide is a(n)

• Element

• Compound

• Homogeneous Mixture

• Heterogeneous Mixture