Presentation on theme: "Mixtures Mixture: a combination of two or more substances that are not chemically combined. Can only become a mixture if they do not react to form a compound."— Presentation transcript:
Mixtures Mixture: a combination of two or more substances that are not chemically combined. Can only become a mixture if they do not react to form a compound. There are no chemical changes that happen in a mixture. In some mixtures you can see the components (ex. Pizza) and in others you cannot (ex. Salt water)
Separating Mixtures Distillation: a process that separates a mixture based on the boiling points of the components. Magnets: used to separate different metals based on their physical properties. Centrifuge: a way of separating mixtures into their components by their densities. Evaporation: A way of separating mixtures by using a change of state from a liquid to a gas.
Comparing Mixtures and Compounds MixturesCompounds Made of elements, compounds, or bothMade of elements No change in original properties of components Change in original properties of components Separated by physical meansSeparated by chemical means Formed using any ratio of componentsFormed using a set ratio of components
The Ratio of Components in a Mixture Components of a mixture do not need to be mixed in a definite ratio. Ex. Granite: Made from feldspar, mica, and quartz minerals. Feldspar is pink. Mica is black. Quartz is clear. Can you explain the difference in these?
Solutions Solution: a mixture that appears to be a single substance. They are composed of particles of two or more substances which are distributed evenly among each other. Have the same appearance and properties throughout the mixture.
Solutions Cont. Dissolving: the process in which particles of substances separate and spread evenly throughout the mixture. Solute: The substance that is dissolved. Solvent: the substance in which the solute is dissolved. Soluble: means a substance is “able to dissolve.” Insoluble: means a substance is “unable to dissolve.
Soluble & Insoluble A substance that is soluble will dissolve into a solute and become a solution. A substance that is insoluble will not dissolve into a solute and will become a mixture.
Which is the solvent? Which is the solute? When a solid dissolves into a liquid: the solid is the solute and the liquid is the solvent. When two liquids or gasses form a solution: The substance that is present in the largest amount is the solvent… the other then, must be the solute.
Examples of Different States in Solutions StatesExamples Gas in gasDry air (oxygen in nitrogen) Gas in liquidSoft drinks (carbon dioxide in water) Liquid in liquidAntifreeze (alcohol in water) Solid in liquidSalt Water (salt in water) Solid in solidBrass (zinc in copper)
Particles of Solutions Particles in solutions are so small they never settle out. They cannot be removed by filtering. Particles are so small they don’t even scatter light.
Concentration of Solutions Concentration: a measure of the amount of solute dissolved in a solvent. Can be expressed as grams of solute per milliliter of solvent. (g/ml) Dilute: a solution with less solute. Concentrated: a solution with more solute. Dilute and Concentrate do not tell you how much solute is has been dissolved. They can only compare.
Solubility Solubility: the ability of the solute to dissolve in a solvent at a certain temperature.
Dissolving gases in liquids Gases become less soluble in liquids as the temperature is raised. Ex. Pop becomes “flat” in warm temperatures because gasses cannot stay dissolved in warmer temperatures.
Dissolving Solids Faster in Liquids Mixing: by stirring or shaking causes the solute particles to separate from one another and spread out more quickly among the solvent particles. Heating: Causes particles to move more quickly. The solvent particles can separate the solute particles and spread them out more quickly. Crushing: The solute increases the amount of contact it has with the solvent. The particles of the crushed solute mix with the solvent more quickly.
Suspensions & Colloids Suspension: a mixture in which particles of a material are dispersed throughout a liquid or gas but are large enough that they settle out. Ex. Snow Globe Colloid: a mixture in which the particles are dispersed throughout but are relatively small and are fairly well mixed. Ex. Milk, mayonnaise, stick deodorant