Question

which is a characteristic of mixtures?
○ they are chemically bonded together.
○ they can be classified as pure substances.
○ they have fixed ratios between their components.
○ they can be separated by physical processes.

Explanation:

• For the first option: Mixtures have components that are not chemically bonded (chemical bonds are in compounds), so this is incorrect.
• For the second option: Mixtures are made of two or more substances, while pure substances are single - type (element or compound), so mixtures aren't pure substances, this is wrong.
• For the third option: Mixtures have variable component ratios (unlike compounds with fixed ratios), so this is incorrect.
• For the fourth option: Mixtures' components can be separated by physical processes (like filtration, distillation) since they aren't chemically bonded.

Answer:

D. They can be separated by physical processes. (assuming the options are labeled A - D as is common, with the last option being the correct one)