Question

refer to the slide show above, test tube 2. why did the water level in tube 2 become lower after the salt cubes dissolved? the water molecules were destroyed by the salt. the water was displaced by the salt. the atoms of na and cl occupied the spaces between the water molecules. the water mixed with the salt.

Explanation:

When salt (sodium - chloride, NaCl) dissolves in water, the Na and Cl ions separate and fit into the spaces between the water molecules. This does not displace the water in the sense of pushing it out to increase the volume, but rather fills the intermolecular voids, causing the overall volume to decrease slightly and the water - level to lower. Water molecules are not destroyed by salt, and "the water was displaced by the salt" is incorrect as it's not a simple displacement like with a solid object that doesn't dissolve. "The water mixed with the salt" is a very general statement and doesn't specifically explain the volume change.

Answer:

The atoms of Na and Cl occupied the spaces between the water molecules.