Solutions, Suspensions Colloids
Jan 19, 2018
Solutions, Suspensions Colloids
Solutions Appears to be a single substance
but really two or more substances dissolved in a solvent and evenly distributed
Very small particles that never settle out
Homogeneous
Examples of Solutions Alloys – solid solutions of metals or
non-metals dissolved in metals Iced tea, salt water, soda, gasoline
Solute versus Solvent A solute is the substance in a solution that
gets dissolved A solvent is the substance in a solution
that does the dissolving If something is soluble, the solute can be
dissolved in a particular solvent If something is insoluble, the solute will
not be dissolved in a particular solvent Solutes can be soluble in some solvents
but insoluble in others
Concentration The comparison of solute to solvent When there is not a lot of solute
compared to solvent, the solution is dilute
When there is a lot of solute compared to solvent, the solution is concentrated
Saturated Solutions Saturated solution – contains all of
the solute it can hold at a given temperature. If you add even one more molecule of
the solute, it will fall out of solution and rest on the bottom
Unsaturated Solutions Contains less solute than it can
hold at a given temperature Can add more solute and it wont fall
out of the solution
Supersaturated Solution Solution that holds more than it
usually would at a given temperature
Solubility The amount of solute needed to make a
saturated solution in a given solvent at a given temperature
For solid solute in liquid solvent – solubility rises as temperature rises.
For gas solute in a liquid solvent – solubility lowers as temperature risesex – soda goes flat at warm temperatures
Methods to speed up dissolving Crushing a solute increases the surface area of
the solute allowing more solvent to surround it thus dissolving it faster Ex. Putting butter in macaroni and cheese
Heating a solution increases the energy of the molecules making them move more quickly thus spreading the solute throughout the solvent and speeding up the rate at which the solute dissolves Ex- cooking iced tea
Mixing has the same effect as heating does Ex- making chocolate milk
Suspensions A suspension is a mixture in which
particles of material are dispersed throughout a liquid or gas and are large enough to settle out
The particles are insoluble Heterogeneous mixtures Ex snow globe
Colloids Have properties of both solutions and suspensions Particles in a colloid are much smaller than
particles in a suspension Colloids have the same definition as suspensions
in that a colloid is a mixture in which particles of material are dispersed throughout a liquid or gas, but the particles of a colloid are not large enough to settle out
Particles in a colloid scatter light Ex milk, fog, jello