Solutions
Solutions are homogenous mixtures that exist in all states of matter. Commonly, we deal with liquid solutions. A solution contains two parts: the solute and the solvent. The solute is the substance that dissolves, and the solvent is the substance that does the dissolving. Water is a universal solvent.
Solution concentration refers to the amount of solute dissolved in a given amount of solvent. A dilute solution contains a small quantity of solute relative to the solvent, whereas a concentrated solution contains a large quantity of solute relative to the solvent. Solutions can be expressed as percent by mass, percent by volume, and molarity. Molarity is the amount of moles of solute per liter of solution. The unit for molarity is either "M" for "molar," or as noted in the IB, "mol dm^-3"
Concentration of solution (mol dm^-3) = amount of solute in moles/volume of solution in dm^3.
Note: Be careful with distinguishing between "dm^3" and "dm^-3." The three becomes negative when it is no longer in the denominator.
When solutions are diluted, this means more solvent has been added, and therefore the concentrations will change. The formula for molar dilution is:
M1V1 = M2V2
where "M" represents molarity, "V" represents volume, "1" represents initial conditions, and "2" represents final conditions.
Solutions can be soluble or insoluble. This basically means that they may or may not dissolve in aqueous solutions. Knowledge of which compounds are soluble in aqueous solutions leads to an understanding of whether a precipitate will or will not form. A standard table of solubility rules is useful in determining whether a compound is soluble or insoluble. This table of Solubility Rules from UC Davis' Chemwiki lists the basics.
Solution concentration refers to the amount of solute dissolved in a given amount of solvent. A dilute solution contains a small quantity of solute relative to the solvent, whereas a concentrated solution contains a large quantity of solute relative to the solvent. Solutions can be expressed as percent by mass, percent by volume, and molarity. Molarity is the amount of moles of solute per liter of solution. The unit for molarity is either "M" for "molar," or as noted in the IB, "mol dm^-3"
Concentration of solution (mol dm^-3) = amount of solute in moles/volume of solution in dm^3.
Note: Be careful with distinguishing between "dm^3" and "dm^-3." The three becomes negative when it is no longer in the denominator.
When solutions are diluted, this means more solvent has been added, and therefore the concentrations will change. The formula for molar dilution is:
M1V1 = M2V2
where "M" represents molarity, "V" represents volume, "1" represents initial conditions, and "2" represents final conditions.
Solutions can be soluble or insoluble. This basically means that they may or may not dissolve in aqueous solutions. Knowledge of which compounds are soluble in aqueous solutions leads to an understanding of whether a precipitate will or will not form. A standard table of solubility rules is useful in determining whether a compound is soluble or insoluble. This table of Solubility Rules from UC Davis' Chemwiki lists the basics.