Pure Substances vs Mixtures
What is a pure substance?
A material that contains only one type of particle.
What is a solution?
A homogeneous mixture of two or more substances where particles are evenly distributed.
What is a solution of gas in liquid?
Carbonated drinks (carbon dioxide in water).
Whatkind of mixture can be separated using filtration?
Insoluble solids from liquids (suspensions)
Which separation technique is used in water treatment plants?
Filtration
What is a mixture?
A combination of two or more substances that are not chemically combined.
What is a suspension?
A heterogeneous mixture where solid particles are suspended in a liquid but settle over time.
Give an example of a liquid dissolved in another liquid.
Alcohol in water.
What technique is used to separate dissolved substances from water?
Evaporation
Which separation technique is used to refine petroleum?
Distillation
Is salt water a pure susbtance or a mixture?
A mixture (solution)
What is a colloid?
A mixture where particles are small enough to stay suspended and don’t settle, but are large enough to scatter light
What is the solvent and solute in a solution of salt in water?
Water is the solvent and salt is the solute
What separation technique is used to separate different colors in ink?
Chromatography
How is salt harvested from seawater?
Evaporation
If you have a container with two layers of different liquids, how can you tell if it's a mixture or a pure substance?
It is a mixture if the two liquids do not chemically combine and remain separate layers. A pure substance would have a uniform composition throughout.
What’s the main difference between a solution and a suspension?
Solutions have particles that are too small to see and don’t settle, while suspensions have larger particles that settle over time.
How would you arrange solutions, suspensions and colloids based on decreasing particle size? (largest particles to smallest)?
Suspensions, colloids, solutions
How would you complete this sentence?
Distillation is a process that separates substances based on their different _______ ________.
Boiling Points
What technique would be used to separate cream from milk?
Centrifugation
Explain why air is considered a mixture rather than a pure substance.
Air is a mixture because it contains a variety of gases (e.g., nitrogen, oxygen, carbon dioxide) that are not chemically combined and can be separated by physical means.
How would you distinguish between a colloid and a suspension if you cannot see the particles?
You could use the Tyndall effect. Shine a light through the mixture; if the light is scattered (making a visible beam), it’s a colloid. If the light passes through without scattering, it’s likely a suspension.
What is the name gievn to a solution when the amount of solute in a solvent is so high that not all of it will dissolve?
Saturated
Which to methods would you use to separate a mixture of sand and salt?
Filtration and evaporation
How chromatography help identify different pigments in a mixture of inks?
Chromatography separates the different pigments based on their movement through a medium (e.g., paper) using a solvent. As the solvent moves up the paper, different pigments travel at different rates, allowing them to be identified and separated.