Question

Solids will usually sink when placed in their own liquids. Which is an exception?

carbon dioxide
baking soda
steel
water



An atom of lithium (Li) forms an ionic bond with an atom of chlorine (Cl) to form lithium chloride. How are the valence electrons of these atoms rearranged to form this bond?

A few valence electrons are shared between the atoms.
Many valence electrons are shared between the atoms.
Electrons are transferred from the chlorine atom to the lithium atom.
Electrons are transferred from the lithium atom to the chlorine atom.



The density of solid aluminum is 2.70 g/cm3. If a 1g piece of aluminum is dropped in a cup of water, what will happen to the aluminum? (The density of water is 1.00 g/cm3.)

It will sink to the bottom.
It will float to the top.
It will hover in the middle.
It will move up and down.


While researching scuba diving, Pablo reads how hot a tank should get while being filled with air. Which law best explains why the scuba tank would heat up?

Gay-Lussac’s law, because as the pressure decreases, the temperature increases
Gay-Lussac’s law, because as the pressure increases, the temperature increases
Boyle’s law, because as the volume decreases, the temperature increases
Boyle’s law, because as the pressure increases, the temperature increases

Answer 1

1) Water — ice is less dense than liquid water, so solid water (ice) floats.

2) Electrons are transferred from the lithium atom to the chlorine atom — Li loses its one valence electron to Cl, forming Li+ and Cl− (ionic bond).

3) It will sink to the bottom — aluminum’s density (2.70 g/cm3) is greater than water’s (1.00 g/cm3), so it won’t displace enough water to float.

4) Gay-Lussac’s law, because as the pressure increases, the temperature increases — for a (nearly) constant-volume tank, raising pressure raises temperature.