Question

a student receives a beaker that contains sand, water, and salt mixed together. the student performs a two - step process to separate all of the substances, as shown in the table.

step	process	observation
2	heat the beaker with salt and water on a hot plate.	the water evaporates, leaving the salt as a white powder on the bottom of the beaker.

which statement best classifies the contents of the beaker?

• the beaker contains a homogeneous mixture after step 1 and an element after step 2. the beaker contains a homogeneous mixture after step 1 and an element after step 2.
• the beaker originally contains a heterogeneous mixture, but after step 1, it contains one compound.
• the beaker contains a heterogeneous mixture after step 1 and a compound after step 2.
• the beaker originally contains a heterogeneous mixture, and after step 1, it contains a homogenous mixture.

Explanation:

1. Analyze the original mixture: Sand, water, and salt mixed together. Sand is a solid, water is liquid, and salt dissolves in water. Since sand doesn't mix uniformly (you can see or separate it), the original mixture is heterogeneous.
2. Analyze Step 1: After filtering, sand is removed, and we have a clear liquid of salt and water. Salt dissolved in water forms a homogeneous mixture (solution) because the salt is evenly distributed in water.
3. Evaluate each option:

• First option: After Step 2, we have salt (a compound, not an element), so this is wrong.
• Second option: After Step 1, we have a mixture (salt + water), not a compound, so wrong.
• Third option: After Step 1, it's homogeneous (not heterogeneous), so wrong.
• Fourth option: Original is heterogeneous (sand, water, salt), after Step 1, salt water is homogeneous. This matches.

Answer:

The beaker originally contains a heterogeneous mixture, and after Step 1, it contains a homogenous mixture.