Understanding Mixtures and Pure Substances

What happens when food color is added to water?

• It sinks to the bottom.

• It forms a separate layer.

• It mixes uniformly throughout the water.

• It evaporates.

Which of the following is a pure substance?

• Gold

• Saltwater

• Air

• Sand

What is the main difference between elements and compounds?

• Elements have variable compositions, compounds have fixed compositions.

• Elements can be separated physically, compounds cannot.

• Elements are mixtures, compounds are pure substances.

• Elements are made of one kind of atom, compounds are chemically bonded atoms.

How can mixtures be separated?

• By burning

• By dissolving

• By physical means

• By chemical reactions

What is a key characteristic of homogeneous mixtures?

• They have visible boundaries.

• They cannot be separated.

• They are always solid.

• They have a uniform composition.

Which of the following is an example of a homogeneous mixture?

• Sand and water

• Ink

• Oil and water

• Salad

What distinguishes heterogeneous mixtures from homogeneous mixtures?

• They are always liquid.

• They have a uniform composition.

• They cannot be separated.

• Their components are visibly distinct.

Which of the following is a heterogeneous mixture?

• Seashell and cement

• Brass

• Butter caramel

• Ink

What is brass primarily composed of?

• Iron and carbon

• Copper and zinc

• Aluminum and magnesium

• Copper and tin

Why is copper not considered a mixture?

• It is an element.

• It is a homogeneous mixture.

• It is a heterogeneous mixture.

• It is a compound.