Question

A scientist filters a sample of river water. The data from this process are listed below.

These data support which of the following descriptions of the sample?
A
It is a pure substance because solid particles cannot pass through the filter paper.
B
It is a pure substance because the river water is composed only of free elements.
C
It is a mixture because dissolved ions in the water pass through the filter paper.
D
It is a mixture because solid particles are separated from the river water.

Answer 1

The data from the filtration process indicate:

D. It is a mixture because solid particles are separated from the river water.

Filtration is a method used to separate solid particles (in this case, from the river water), which is a characteristic of a mixture. If it were a pure substance, there wouldn't be solid particles to separate.