Practice identifying and describing mixtures and solutions, including solutes, solvents, and physical methods for separating substances.
Read each problem carefully. Answer in complete sentences and show your thinking when needed.
Identifying mixtures, solutions, solutes, and solvents
Chemistry - Grade 6-8
- 1
A student stirs table salt into a glass of water until the salt can no longer be seen. Is this mixture a solution? Explain why.
- 2
In a cup of hot cocoa made from cocoa powder and water, the cocoa powder does not fully dissolve and some settles at the bottom. Is this a solution or not? Explain your answer.
- 3
In salt water, identify the solute and the solvent.
- 4
A trail mix contains raisins, peanuts, and chocolate chips. Is trail mix a homogeneous mixture or a heterogeneous mixture? Explain how you know.
- 5
Describe one way to separate sand from water. Explain why that method works.
- 6
Sugar is stirred into warm tea until it disappears. What evidence suggests that a solution has formed?
- 7
A student mixes oil and water in a beaker. After a few minutes, two layers form. What does this show about the mixture?
- 8
If more and more salt is added to water until no more salt dissolves, what is this type of solution called?
- 9
Explain how evaporation can be used to separate dissolved salt from salt water.
- 10
Air is made of several gases mixed evenly together. Is air best described as a solution, a homogeneous mixture, or a heterogeneous mixture? Explain.
- 11
A student says, "All mixtures are solutions." Is this statement correct? Explain why or why not.
- 12
Give one example of a solution and one example of a heterogeneous mixture from everyday life. Explain the difference between them.