Are you ready to master the ultimate mixtures quiz for grade 7? Our Master Grade 7 Mixtures Quiz - Test Your Chemistry Skills! invites curious students to explore mixtures and solutions through engaging types of mixtures quiz challenges. You'll tackle everything from separation techniques questions to a components of solutions quiz and even uncover if rocky road ice cream is a substance or a mixture. Whether you're reviewing from solutions and mixtures lessons or brushing up on facts about mixtures and solutions , this free quiz helps you learn, test your knowledge, and build confidence. Dive in and start your chemistry journey today!
What is a mixture?
A pure substance composed of a single element
A substance made by combining two or more elements or compounds that are not chemically bonded
A compound with a fixed chemical formula
A pure substance that cannot be separated by physical methods
A mixture consists of two or more substances physically combined without forming chemical bonds, meaning each substance retains its own properties. Mixtures can be separated by physical methods such as filtration or evaporation. Unlike compounds, mixtures do not have fixed ratios of components. Learn more.
What type of mixture is salt dissolved in water?
Homogeneous mixture
Heterogeneous mixture
Suspension
Colloid
Salt water is a homogeneous mixture, also known as a solution, because the salt (solute) is evenly distributed throughout the water (solvent) at the molecular level. You cannot distinguish the salt particles by sight or filtration once dissolved. The composition is uniform throughout the solution. Read more.
Which separation method would you use to separate sand from water?
Filtration
Distillation
Chromatography
Evaporation
Filtration separates solid particles like sand from liquids by passing the mixture through a porous material such as filter paper. The sand is trapped, while water passes through. It is a quick and common physical separation technique for insoluble solids. Learn about filtration.
In a solution, what is the solvent?
The substance present in the smallest amount
The substance that dissolves the solute
The undissolved solid particles
A heterogeneous mixture
The solvent is the component of a solution that dissolves the solute and is usually present in the largest amount. For example, water is the solvent in salt water solution. It determines the phase of the solution. More about solvents.
In a solution of sugar water, sugar is called the…
Solvent
Solute
Filtrate
Precipitate
The solute is the substance that is dissolved in a solvent to form a solution, like sugar dissolving in water. It is present in a smaller amount compared to the solvent. After dissolution, it cannot be distinguished by sight. See details.
Which method can separate magnetic materials such as iron filings from a mixture?
Evaporation
Filtration
Magnetism
Distillation
Magnetism uses a magnet to attract and remove magnetic substances like iron filings from a mixture. It is a simple and effective way to separate magnetic materials from non-magnetic ones. No heating or complex apparatus is required. Learn about magnetism.
Which of the following is a heterogeneous mixture?
Salt dissolved in water
Air
Oil and water
Sugar solution
Oil and water form a heterogeneous mixture because the two liquids do not mix uniformly, resulting in distinct layers. You can see the separate oil droplets or layer on top of the water. This non-uniform composition is characteristic of heterogeneous mixtures. More on heterogeneous mixtures.
Which separation method is best for recovering dissolved salt from saltwater?
Filtration
Evaporation
Chromatography
Distillation
Evaporation removes the water by converting it to vapor, leaving solid salt crystals behind. This method exploits differences in boiling points of the components. It is commonly used to extract salts from saline water. More details.
What is the name of the process where a liquid is poured off from settled solids without disturbing them?
Sedimentation
Decantation
Filtration
Distillation
Decantation involves carefully pouring off the liquid layer above settled solids after sedimentation. It is a simple way to separate mixtures where solid particles settle by gravity. No specialized equipment is needed beyond a container. Read more.
Which separation technique is used to separate a mixture of alcohol and water?
Filtration
Distillation
Evaporation
Chromatography
Distillation separates components based on different boiling points; alcohol boils at a lower temperature than water, allowing it to vaporize first and then condense separately. It is widely used to purify liquids. Fractional distillation may be required for close boiling points. Learn about distillation.
What term describes the maximum amount of solute that can dissolve in a solvent at a specific temperature?
Saturation point
Solubility
Concentration
Density
Solubility defines the maximum quantity of a solute that can dissolve in a solvent at a given temperature to form a saturated solution. It is usually expressed in grams of solute per 100 grams of solvent. Temperature changes can affect solubility. More on solubility.
In filtration, what is the name of the solid collected on the filter paper?
Filtrate
Permeate
Residue
Solvent
Residue refers to the solid particles that are trapped on the filter paper during filtration. The liquid that passes through is called the filtrate. Understanding these terms is essential in separation techniques. Discover more.
What does the concentration of a solution express?
The amount of solute dissolved in a given amount of solvent or solution
The boiling point of the solution
The particle size of the solute
The density of the solvent
Concentration measures how much solute is present relative to the amount of solvent or total solution, commonly expressed as molarity or percentage by mass or volume. It indicates the strength of a solution. Changing concentration affects physical properties like boiling point. Khan Academy.
Which technique uses rapid spinning to separate suspended particles from a liquid?
Evaporation
Centrifugation
Distillation
Decantation
Centrifugation spins mixtures at high speed to force denser particles outward, separating them from the liquid phase. It is especially useful to separate small particles or cells in a suspension. The result is a pellet and supernatant. Learn about centrifugation.
Which separation method relies on a stationary phase and a mobile phase to separate components?
Chromatography
Distillation
Filtration
Centrifugation
Chromatography separates components based on their distribution between a stationary phase and a mobile phase. Different substances travel at various speeds, causing separation. It is widely used in chemical analysis. More on chromatography.
What principle does fractional distillation exploit to separate complex liquid mixtures?
Differences in density
Differences in boiling points
Differences in solubility
Differences in polarity
Fractional distillation separates liquids by repeatedly vaporizing and condensing them according to their specific boiling points. This creates more efficient separation for mixtures with close boiling points. It is commonly used for refining crude oil. Fractional distillation.
Which apparatus is used to separate two immiscible liquids based on density differences?
Separatory funnel
Chromatography plate
Rotary evaporator
Centrifuge
A separatory funnel allows two immiscible liquids to form distinct layers, and the denser liquid can be drained off from the bottom. It is frequently used in organic chemistry labs. The stopcock controls the release of each layer. Learn about separatory funnels.
Which method uses controlled cooling of a saturated solution to form pure solid crystals from the solution?
Filtration
Crystallization
Distillation
Centrifugation
Crystallization purifies compounds by forming high-purity crystals from a supersaturated solution as it cools. Impurities remain in the liquid phase. It is commonly used for purifying salts and organic compounds. Learn more.
What term describes a heterogeneous mixture where solid particles are large enough to eventually settle out of a liquid?
Solution
Colloid
Suspension
Emulsion
A suspension is a heterogeneous mixture with particles large enough to settle at the bottom if left undisturbed. Examples include muddy water and flour in water. The particles can be separated by filtration or decantation. More on suspensions.
Which of these is an example of an alloy?
Air
Milk
Stainless steel
Salt water
An alloy is a homogeneous mixture (solid solution) of metals or metals with non-metals, like stainless steel (a mixture of iron, carbon, and chromium). Alloys have metallic bonding and improved properties. They are engineered for strength and corrosion resistance. Learn more.
How would you separate a mixture of iron filings, sand, and salt?
Use a magnet to remove iron, then filter out sand and evaporate the filtrate to get salt
Distill the mixture directly to separate all components
Use chromatography to separate each component
Add acid to dissolve all components
First, magnetism removes iron filings. Then, dissolving the remaining mixture in water dissolves the salt but not the sand; filtration separates the sand. Finally, evaporation of the saltwater solution yields salt crystals. This multi-step process exploits different physical properties. See separation steps.
Because ethanol forms a constant-boiling mixture (azeotrope) with water
Because ethanol and water have identical densities
Because ethanol decomposes at high temperature
Because water evaporates before ethanol
Ethanol and water form an azeotrope at about 95.6% ethanol, boiling at a constant temperature, so simple distillation cannot separate them further. The vapor has the same composition as the liquid at this point. Breaking the azeotrope requires special techniques. Learn about azeotropes.
In paper chromatography, what does the Rf value represent?
The ratio of the distance moved by the solute to the distance moved by the solvent front
The retention time of the compound
The concentration of the solute
The density difference between phases
The Rf (retention factor) value is calculated as the distance a compound travels divided by the distance the solvent front travels. It is characteristic for a given compound under specific conditions. Rf values help identify substances in a mixture. More on Rf value.
A solution is prepared by dissolving 5 grams of salt in 20 grams of water. What is the mass percent of salt in the solution?
20%
25%
15%
80%
Mass percent is calculated by dividing the mass of solute by the total mass of solution and multiplying by 100. Here, 5 g salt / (5 g salt + 20 g water) × 100 = 20%. This indicates salt makes up 20% of the solution’s mass. Learn more about mass percent.
Which technique can be used to obtain absolute (100%) ethanol from a 95.6% ethanol-water azeotrope?
Add a drying agent like anhydrous calcium oxide to bind water, then distill
Simple distillation under normal pressure
Paper chromatography
Centrifugation
To break the ethanol-water azeotrope and obtain pure ethanol, you can add a drying agent (such as anhydrous calcium oxide) which absorbs water, and then perform distillation. This removes water chemically rather than relying on boiling point differences. Azeotropes cannot be separated by distillation alone. More on breaking azeotropes.
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Study Outcomes
Understand fundamental mixture concepts -
Learn to distinguish between homogeneous and heterogeneous mixtures as introduced in the mixtures quiz for grade 7.
Differentiate substances and mixtures -
Analyze real-life examples like rocky road ice cream to confidently answer whether it's a substance or a mixture.
Identify components of solutions -
Recognize solutes, solvents, and solution structures by engaging with the components of solutions quiz section.
Apply separation techniques -
Master key methods such as filtration, evaporation, and distillation through targeted separation techniques questions.
Evaluate mixtures in real-world contexts -
Use insights from the types of mixtures quiz to assess and classify everyday mixtures around you.
Cheat Sheet
Types of Mixtures (Homogeneous vs Heterogeneous) -
Homogeneous mixtures have a uniform composition throughout - think salt dissolved evenly in water - while heterogeneous mixtures display visibly different parts, such as rocky road ice cream with nuts and marshmallows. A handy tip is "same all around vs spot the bits" to instantly classify your sample. Britannica and university chemistry sites reinforce these definitions with clear, real-world images.
Components of Solutions: Solute and Solvent -
Every solution consists of a solute (the substance that dissolves) and a solvent (the dissolving medium), like sugar in tea. Remember the mnemonic "S on S" (Solute sits in Solvent) to recall their roles quickly. Khan Academy and official chemistry texts provide practice problems to master concentration calculations (e.g., mass percent = mass of solute ÷ total mass × 100).
Classification by Particle Size: Suspensions, Colloids, and Solutions -
Mixtures can be sorted by particle size: solutions (<1 nm), colloids (1 - 1000 nm), and suspensions (>1000 nm). Use the Tyndall effect (shining a beam of light to see scattering) as your shortcut to spot colloids like milk. Standard science curricula from educational research repositories emphasize this classification for accurate identification.
Memorize the "FDC" trio - Filtration for solids in liquids, Distillation for separating liquids by boiling points, and Chromatography for splitting mixtures on paper or columns. For example, filter muddy water to trap sand, distil seawater to collect fresh water, and perform paper chromatography to separate ink dyes. University lab manuals and chemistry journals detail step-by-step procedures to build confidence.
Real-Life Applications of Separation Methods -
Fractional distillation of crude oil produces fuels of different boiling ranges, and paper chromatography is key in forensic analysis of ink. Water treatment plants combine sedimentation, filtration, and chlorination to ensure safe drinking water. Resources from the National Science Teaching Association (NSTA) showcase these applications with classroom-ready experiments.
