chapter7 Flashcards
Any sample of matter is either a
pure substance or a mixture of pure substances.
Suspension
a mixture i which particles of a material are more or less evenly dispersed throughout a liquid or gas.
Colloid
a mixture consisting of tiny particles that are intermediate in size between those in solutions and those in suspensions, and that are suspended in a liquid, solid, or gas.
emulsion
a colloid in which liquids that normally don’t mix are spread throughout each other.
solution
is a homogenous mixture of two or more substances uniformly dispersed throughout a single phase.
Solute
the substance that dissolves in the solvent.
Solvent
the substance in which the solute dissolves.
miscible
liquids mix to form solutions.
Miscible fluids may be separated by distillation, but only if the mixtures have different boiling points.
Ex. Alcohol and water are miscible with each other.
Alloy
a solid or liquid mixture of two or more metals. Alloys aren’t chemically combined.
Polar Compound
a molecule that has an uneven distribution of electrons. Ex. H2O.
Dissolving depends on forces between particles
To dissolve an ionic substance, water molecules must except a force on the ions that is more attractive than the force between the ions in the crystal.
Hydrogen Bonding
the intermolecular force occurring when a hydrogen atom that is bonded to a highly electronegative atom of on molecule is attracted to two unshared electrons of another molecule.
Non-polar compound
a compound whose electrons are evenly distributed among its atoms.
By kinetic theory of matter, solvent molecules collide and transfer energy to the solute molecule at the surface of the crystal.
This energy and the attractive forces between the solute and solvent molecules causes the surface of the crystal to dissolve.
By the kinetic theory of matter, solutes dissolve faster when the solvent is hot —
cuz of faster moving molecules.
Concentration
the amount of a particular substance in a given quantity of a mixture, solution, or ore.
unsaturated solution
a solution that hasn’t reached the saturation point at given temperature & is able to dissolve additional solute
Saturated solution
a solution that cannot dissolve any more solute under the given conditions.
Supersaturated solution
a solution that holds more dissolved solute than it otherwise would at a given temperature.
Normally achieved by saturating the solution at a higher T and then letting it cool. It will hold all that solute. A single extra atom of the solute will cause the solute to precipitate, until the actual saturation point for the given T.
Solute crystalizes out until
the solution reaches the new saturation point for the cooler temperature. i.e. until the new (lower) saturation point is reached at a lower temperature
Molarity
the concentration of a solution in moles of dissolved solute per liter of solution.
Molarity = moles of solute/ liters of solution, or M = mol/L.
