CHEMISTRY
MRS. SINGH
CHAPTER 15 NOTES
Sxn. 15.1
Most of the important chemistry that keeps plants, animals, and humans
alive occur in aqueous solutions.
A _______________ is a homogeneous mixture – a mixture in which the
components are _____________ distributed.
The SOLVENT is the substance present in the ____________amount.
The SOLUTES are the other substances – present in ___________ amounts.
 Air is a gaseous solution in which _________ is the solvent, and
______ and all the other gases are the solutes.
 Brass is a _________ solution in which _______ is the solvent and
______ is the solute. Solutions containing metals solutes and solvent
are called _________.
 Carbonated water is a solution in which a ____ (CO2) is dissolved in a
___________ (H2O).
 AQUEOUS SOLUTIONS are solutions with _______ as the solvent.
Because so many things dissolve in water, water is called the
‘UNIVERSAL SOLVENT’.
What does it mean when something dissolves and forms a solution?
 When _______ compounds dissolve in water they dissociate into ions.
 The strong ionic forces that hold the sodium chloride crystal together
are overcome by the strong attractions between the ions and the
_______water molecules.
 The ions become surrounded by water molecules and are said to be
HYDRATED
More generally, when solute particles are surrounded by solvent molecules
we say they are SOLVATED.
When ionic substances dissolve in water, they break up into individual
anions and cations. For example, ammonium nitrate DISSOCIATES into
ammonium _________ and nitrate ___________:
NH4NO3 (s) → NH4+ (aq) + NO3– (aq)
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Solubility
 When one substance (solute) __________ in another (solvent) it is
said to be SOLUBLE EX. SALT IS SOLUBLE IN WATER.
 When one substance does not dissolve in another they are said to be
INSOLUBLE EX. Oil is insoluble in water.
 There is usually a limit to the solubility of one substance in another.
 Gases are __________ soluble in each other.
 Some ___________are always mutually soluble.
 The solubility of the solute in the solvent depends on the __________
Higher Temp = Larger solubility of solid in liquid.
Lower Temp = Larger solubility of gas in liquid.
 The solubility of gases depends on ____________.
Higher pressure = Larger solubility
 There is a ________ to how much solute can be dissolved in a given
amount of solvent.
 As you add sugar to a glass of water, the sugar disappears (dissolves).
You eventually get to a point where adding more sugar will
_____dissolve, but will collect at the bottom of the glass.
 When a solution contains as much solute as will dissolve at that
temperature, we say the solution is SATURATED (this depends on the
temperature). A SUPERSATURATED solution has more than the
saturation limit, and is _________. If more solute can dissolve in the
solution, then the solution is UNSATURATED.
 A _________solution is said to be CONCENTRATED(solute > solvent)
 A _______ solution is said to be DILUTE(solute < solvent)
Henry’s Law S1/P1 = S2/P2
At a given temperature, the solubility (S) of a gas in a liquid is directly
proportional to the pressure (P) of the gas above the liquid.
Ex. If 0.24 g of a gas dissolves in 1.0 L of water at 1.5 atm of pressure, how
much of the gas will dissolve if the pressure is raised to 6.0 atm? Assume
the temperature is held constant.
Ex. A gas has a solubility of 0.66 g/L at 10.0 atm of pressure. What is the
pressure on a 1.0 L sample that contains 1.5 g of gas?
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SXN 15.2
Describing Concentration
Percent by mass = mass of solute/mass of solution x 100
Ex. What is the percent by mass of potassium nitrate in a solution made by
mixing 5.4 g of this substance with 260.0 mL of water? (density of water =
1.0 g/mL)
Ex. You have 1500.0 g of a bleach solution. The percent by mass of the
solute sodium hypochlorite, NaOCl, is 3.62%. How many grams of NaOCl
Molarity = mol solute / L solution
Molarity is the number of moles of solute per volume of solution (Liters).
 The amount of solution is described in terms of its concentration
because it’s more convenient to measure the volume of a solution than
its mass.
 The concentration of a solution is the amount of solute in a given
volume of solution.
Ex. A 100.5 mL intravenous (IV) contains 5.10 g of glucose (C6H12O6).
What is the molarity of this solution?
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