Science Chemistry Topics Flashcards

Which method is best for separating salt from a saltwater solution?

Answer: Evaporation

Evaporation removes the water, leaving the dissolved salt behind as solid crystals — the same method used in salt pans.

What is a solution?

Answer: A uniform mixture where one substance dissolves completely in another

A solution is a homogeneous (uniform) mixture where the solute dissolves completely in the solvent and cannot be seen.

Which separation method would you use to remove sand from a sand-and-water mixture?

Answer: Filtration

Filtration passes the mixture through filter paper, which traps the insoluble sand while allowing water to flow through.

Which mixture can be separated effectively using a magnet?

Answer: Iron filings and sand

Iron filings are magnetic and are attracted to a magnet, allowing them to be pulled away from the non-magnetic sand.

In a saltwater solution, what is the solvent?

Answer: Water

Water is the solvent because it is the substance in which the salt (solute) dissolves to form the solution.

What happens when you mix oil and water in a container?

Answer: Oil floats on top of water because oil is less dense and they do not mix

Oil is less dense than water and the two liquids are immiscible (do not mix), so oil always floats on top of water.

Which of the following substances is NOT soluble in water?

Answer: Sand

Sand is insoluble in water — it sinks to the bottom and does not dissolve, unlike sugar, salt, and baking soda.