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 originally contains a heterogeneous mixture, and after step 1, it contains a homogenous mixture
• 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

Explanation:

1. Analyze the original mixture: Sand, water, and salt mixed together. Sand is not dissolved uniformly (you can see sand particles distinct from water - salt solution), so it's a heterogeneous mixture (mixtures with non - uniform composition, different phases or visibly different parts).
2. Analyze after Step 1: After filtering, we have the salt - water solution (clear liquid). A salt - water solution has a uniform composition throughout (you can't distinguish salt from water at a macroscopic level), so it's a homogeneous mixture (mixtures with uniform composition).
3. Analyze other options:

• Option 2: After Step 2, we have salt (a compound, not an element). So this is wrong.
• Option 3: After Step 1, we have a salt - water solution (a homogeneous mixture, not a compound). A compound is a pure substance with a fixed ratio of elements, while a salt - water solution is a mixture. So this is wrong.
• Option 4: After Step 1, we have a homogeneous mixture (salt - water solution), not a heterogeneous mixture. So this is wrong.

Answer:

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