Question

dry ice, or solid carbon dioxide, is used for a number of tasks including food preservation and special effects. the fumes are caused by the carbon dioxide gas being formed directly from solid carbon dioxide. what change of state is this representing?
deposition
condensation
sublimation
evaporation
which physical property describes how well a solid substance resists being scratched?
malleability
viscosity
hardness
density

Explanation:

• For the first question: Sublimation is the process where a solid turns directly into a gas without becoming a liquid. Dry ice (solid carbon dioxide) turning into carbon dioxide gas is an example of sublimation. Deposition is gas to solid, condensation is gas to liquid, and evaporation is liquid to gas.
• For the second question: Hardness is the physical property that describes a solid's resistance to being scratched. Malleability is the ability to be hammered into thin sheets. Viscosity is a liquid's resistance to flow. Ductility is the ability to be drawn into wires.

Answer:

First question: sublimation
Second question: hardness