Mixtures and Solutions: Practice Questions with AnswersCurriculum: Mixtures And SolutionsGrades: 6–9Questions: 12Mode: Practice These are the real questions from this STEPCAI practice lesson. Read each question, pick your answer, then open Show the answer to check yourself and read why it is right. On STEPCAI the same lesson runs interactively: you click an answer and get instant feedback, and a free account keeps your scores. 1. Which statement best describes a mixture?- A compound with atoms joined by chemical bonds in fixed ratios
- Two or more substances combined physically, each keeping its own properties
- A single pure element with only one type of atom
- A new substance formed only by a chemical reaction
Show the answerAnswer: B. Two or more substances combined physically, each keeping its own properties
A mixture is made of two or more substances that are physically combined, not chemically bonded, so each substance keeps its own identity and properties. 2. Salt water is an example of which type of mixture?- Chemical compound
- Pure element
- Homogeneous mixture
- Heterogeneous mixture
Show the answerAnswer: C. Homogeneous mixture
In salt water the salt is dissolved evenly throughout the water, so the composition looks the same in every part; this even, uniform mixing is what makes it homogeneous. 3. In a solution, the substance that gets dissolved is called the:- Solvent
- Residue
- Precipitate
- Solute
Show the answerAnswer: D. Solute
The solute is the substance present in a smaller amount that dissolves into another substance; for example, sugar is the solute when it dissolves in tea. 4. In lemonade, water is considered the:- Solute
- Solvent
- Colloid
- Suspension
Show the answerAnswer: B. Solvent
The solvent is the substance present in the larger amount that does the dissolving; water dissolves the sugar and lemon flavoring, so water is the solvent. 5. A solution is best described as:- A pure substance made of just one kind of particle, so it cannot be separated into any parts
- A mixture where the particles slowly settle to the bottom if it is left standing over time
- A homogeneous mixture where the solute is evenly and completely dissolved in the solvent
- A cloudy mixture whose larger particles scatter a beam of light passing through
Show the answerAnswer: C. A homogeneous mixture where the solute is evenly and completely dissolved in the solvent
A solution is a special kind of homogeneous mixture in which the solute particles are so small and evenly spread that you cannot see them separately, and they will not settle out. 6. Which of these is an example of a heterogeneous mixture?- Salt fully dissolved in water
- Sugar fully dissolved in tea
- Clean air
- Salad with lettuce, tomatoes, and cucumbers
Show the answerAnswer: D. Salad with lettuce, tomatoes, and cucumbers
A salad clearly shows separate, visible pieces of different ingredients, so its composition is not the same throughout; this makes it a heterogeneous mixture. 7. A suspension, such as muddy water, is different from a true solution because in a suspension the particles are:- Chemically bonded together
- Invisible even under a microscope
- Gas particles only
- Too large to dissolve and will eventually settle out
Show the answerAnswer: D. Too large to dissolve and will eventually settle out
In a suspension the particles are relatively large and do not fully dissolve, so gravity pulls them down and they settle to the bottom over time if left undisturbed. 8. Milk is a common example of a:- Single element
- Colloid
- Filtered solution
- Pure compound
Show the answerAnswer: B. Colloid
Milk is a colloid because it contains tiny droplets of fat spread through water; the particles are bigger than in a true solution but too small to settle out like a suspension. 9. When sugar 'dissolves' in water, this means the sugar:- Breaks apart into tiny particles that spread evenly throughout the water
- Disappears completely and no longer exists
- Turns into a gas and evaporates
- Reacts chemically to form a brand new compound
Show the answerAnswer: A. Breaks apart into tiny particles that spread evenly throughout the water
Dissolving is a physical change: the sugar particles separate and spread out evenly among the water molecules, but the sugar is still sugar, just too spread out to see. 10. A saturated solution is one in which:- The mixture is heterogeneous and cloudy, so you can see the separate parts in it
- No solute has been added yet, so the liquid is still a pure solvent
- The solvent has completely evaporated, leaving only the solid solute behind in the dish
- The solvent has dissolved all the solute it can hold at that temperature
Show the answerAnswer: D. The solvent has dissolved all the solute it can hold at that temperature
A saturated solution has reached its limit; the solvent is holding as much dissolved solute as it can at that temperature, so any extra solute added will not dissolve and will settle instead. 11. Filtration is a separation technique best used to separate:- Two gases that are fully mixed together
- Two liquids with different boiling points
- A dissolved solute from its solvent
- Undissolved solid particles from a liquid
Show the answerAnswer: D. Undissolved solid particles from a liquid
Filtration uses a filter with tiny holes that let liquid pass through but trap solid particles that have not dissolved, such as sand in water. 12. Two liquids that mix completely and do not separate, such as water and rubbing alcohol, are described as:- Miscible
- Insoluble
- Saturated
- Immiscible
Show the answerAnswer: A. Miscible
Miscible liquids blend together completely to form a single uniform solution, with no visible boundary or separate layers. More free middle school sample lessonsSee all free sample lessons »
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