Question

rupert had three substances. a brown substance was a liquid at room temperature. he hit each of the other two with a hammer. a blue crystal cracked but did not break. a silver substance flattened but did not crack. which two statements could be true?
a. the brown substance is molecular.
b. the silver substance is ionic.
c. the brown substance is ionic.
d. the blue substance is ionic.

Explanation:

• Molecular substances can exist as liquids at room temperature. Ionic substances are usually solids at room temperature and are brittle (crack when hit). Metallic substances are malleable (flatten when hit).
• The brown substance is a liquid at room temperature. Molecular substances can be liquids at room temperature, while ionic substances are usually solids at room temperature. So the brown substance could be molecular (A could be true).
• The blue crystal cracked (brittle property). Ionic substances are brittle. So the blue substance could be ionic (D could be true).
• The silver substance flattened (malleable property). Ionic substances are brittle, not malleable. So B is false.
• As ionic substances are usually solids at room temperature, C is false.

Answer:

A. The brown substance is molecular, D. The blue substance is ionic