Mixtures 441t4i

SUSPENSION, SOLUBILITY, MISCIBILITY, COLLOID Science Grade 6 Suspension is a heterogeneous mixture, which has particles that do not completely dissolve and settle down at the bottom. Suspensions are cloudy mixtures. Some substances do not dissolve completely in solvents. The particles that do not dissolve settle down at the bottom of the container. An example of mixture is sand and water used as construction materials. You had observed that particles settle down at the bottom of the glass. The particles do not spread evenly unlike the solution. This mixture is called suspension. Solubility is the ability of a solute to dissolve in a solvent at a given temperature.     

Usually the higher the temperature, the faster a solute can be dissolved in a solvent. The nature of solute and the amount of solvent also determine how fast the solute dissolves in a solvent. The size of the particles affects the dissolving process. The finer the particles are, the faster the solute dissolves. The manner of stirring is also a factor to dissolve a solute in a solvent.

Factors affecting solubility: a. Amount of solute b. Size of solute particles c. Temperature of solvent d. Nature of solute e. Nature of solvent f. Amount of solvent Miscibility is another factor that affects the solubility of substances.  It is the property of a substance to mix evenly and completely with another substance.  Some liquids are miscible like alcohol and water that dissolve completely with one another.  Other liquids are immiscible like oil and water which will not mix together or do not dissolve completely with one another.  There are also liquids that are partially miscible like gasoline and alcohol that mix only to some extent Types of colloids A sol is a solid dispersed in either solid or a liquid. Examples of solid sols (solid dispersed in solid) are opal, pearls, and other colored glass like stained glass. Examples of solid dispersed in liquid are blood, paints, gum, muddy water, and some forms of pigment ink.

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An emulsion is a liquid dispersed in either a liquid or solid. Examples of emulsions are milk, codliver oil, butter, mayonnaise, and most ointments and creams used in medicines and cosmetics. The components of an emulsion usually do not mix. An emulsifying agent is mixed to form a stable emulsion. Mayonnaise, for example, is a mixture of oil in lemon or vinegar with egg yolks as an emulsifying agent to stabilize the emulsion. Fresh milk is usually homogenized to reduce the size of the fat particles and prevent the separation of an oily upper layer of cream from the colloidal suspension of protein. Aerosols are suspensions of liquid or solid particles in a gas. Clouds and fog are natural aerosols, which consist of water droplets dispersed in air. Dusty air and smoke are aerosols, too. Insecticides, perfume spray, spray paint are artificial aerosols dispersed in the air. Foams are colloids which consist of gas dispersed in liquid (liquid foams) or solid (solid foams). Whipped cream, froth on a glass on a beer, and soap lather are liquid foams. Styrofoam, pumice, yeast bread, and cake icing are solid foams. Gels are colloids which consist of liquid dispersed in solid. Your favorite gelatin dessert is a gel’ another example is silica gel. Silica gel is placed in small packages in packets of medicines and vitamin pills to keep them dry. Shoe polish, jellies, and jam are gels.

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