Q: Sodium is an example of what sort of thing that cannot exist by itself in nature? Choices: - concept - compound - aspect - element A:
element

Q: What is a force that opposes motion between any surfaces that are touching? Choices: - vibration - tension - gravity - friction A:
friction

Q: What molecules are usually insoluble in water? Choices: - polar - acids - ions - non-polar A:
non-polar

Q: A colloid is a homogeneous mixture with medium-sized what? Choices: - atoms - solutions - molecules - particles A:
particles