Classifying Solutions
Types of Solutions
Gas Solid/Gas Liquid/Gas Gas
Solid Solid/Solid Liquid/Solid Gas
Liquid Solid/Liquid Liquid/Liquid Gas
Solution-a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent)
Solvent- A substance that can dissolve another substance, or in which another substance is dissolved into
Solute-The minor component in a solution, dissolved in the solvent
Aqueous-contains water
Alloy-a solid solution or two or more metals
Solubility-The maximum amount of solute that will dissolve in a given quantity of solvent at a specific temperature
Saturated Solution-a solution that cannot dissolve more solute (contains maximum amount of solute at which the solution exists)
Unsaturated Solution-a solution that could dissolve more solute (contains less solute than the maximum amount possible is dissolved in the solution)
Supersaturated Solution-a solution that contains more dissolved solute than a saturated solution at the same temperature
Determining the type of solution
-Add a seed crystal of solute
-Dissolves= unsaturated
-Does not dissolve= saturated
-Begins to crystallize= supersaturated
Solubility
Expressed in grams of solute per 100g of solvent
Solute Solubility (g solute/100g solvent) Qualitative Solubility description
Less than 0.1 Insoluble
0.1>1 Slightly Soluble
1-10 Soluble
10< Very soluble
e.g. A 3.20g sample of a salt dissolves in 9.10g of water to give a saturated solution at 25*C. What is the solubility (in g salt/100g of water) of the salt?
Solute = 3.20gSalt = x _
Solvent 9.10gH2O 100gH2O
x=3.20gSalt(100gH2O)
9.10gH2O
x=35.2g
Factors that Affect Solubility
Forces that act between the particle of the substances in solutions:
-forces that attract particle of the solute to each other
-forces that attracts particle of the solute to particles of the solvent
-forces that attract particles of the solvent to each other
Solubility in Water
-The polar nature of water molecules enables water to dissolve a wide range of solutes
-Most ionic compounds are soluble in water
1.Electrical attraction between the polar water molecules and the ions pulls ions from the surface of the solute
2.Polar water molecules surround the separated ions in a process called hydration, and ions disperse uniformly in solution
Polar compounds dissolve in water
Nonpolar compounds don’t dissolve in water
Nonpolar compounds can dissolve in nonpolar solvents
Conductivity of Aqueous Solutions
Solutions of ionic compounds can conduct electricity.
Temperature and Solubility (Solid in Liquid)
For most ionic solids, solubility increases as temp increases.
Temperature and Solubility(Liquid in Liquid, Gas in Gas)
Temperature change has little effect on the solubility of one liquid in another one or one gas in another
Temperature and Solubility(Gas in Liquid)
The solubility of a gas in a liquid decreases as the temperature increases
Pressure and Solubility(Gas in Liquid)
The solubility of a gas in a liquid is directionally proportional to the pressure of that same particular gas above the liquid
Factors that Affect Rate of Dissolving
-agitation or mixing(stirring)
-temperature increases
-increased surface area of the solute
Concentrations of Solutions as a %
Concentration-the ratio of the quantity of solvent or the quantity of solution
Concentrated-having a high ratio of solute to a solution
Dilute-having a low ratio of solute to solution
% (Mass/Volume)
-a ratio of the mass of solute to the volume of solution, expressed as a percent
%(m/v)=m of solute (g) x100%
v of solution (mL)
% (Mass/Mass)
-a ratio of mass of solute to mass of solution, expressed as a percent
%(m/m)=m of solute (g) x100%
m of solution (g)
% (Volume/Volume)
-a ratio of the volume of solute to the volume of solution, expressed as a percent
%(v/v)= v of solute (mL) x100%
v of solution (mL)
ex.(m/v but applies to all % questions)
g:msolute=17.5g msolvent=350mL
r: %(m/v)= ?
a: %(m/v)=msolute x100%
msolvent
m: =17.5g x100%
350mL
=5.00% [3 sig digs]
Very Small Concentrations of Solutions
Parts per million (ppm)
-a ratio of solute to solution x106
ppm=m of solute (g) x106
m of solution (g)
Parts per billion (ppb)
-a ratio of solute to solution x109
ppb=m of solute (g) x109
m of solution (g)
ex.(ppm but same steps for ppb)
g:mNaF=32.2mg=3.22x10-2g
mH2O=20.0kg=2.00x104g
r: ppm(m/m)= ?
a: ppm(m/m)=mass of solute x106
mass of solution
m: ppm(m/m)=3.22x10-2g x106
2.00x104g+3.22x10-2g
=1.61ppm(m/m)
Molar Concentrations
-the amount in moles of solute dissolved in 1L of solution
equation: C= n/V
ex. Molar concentration
g:c=0.154mol/L
V=500mL=0.500L
r:n=? m=?
a:n=cV
m:n=0.154mol/L(0.500L)
=0.077mol
m=Mn
=(22.989770g/mol)(0.077mol)
=1.77g
ex. Molar concentration of ions
g:n=0.212molFeCl3
V=0.175mL
r:c=?
a:c=n/v
m:c=0.212molFeCl3/0.175mL
=1.21mol/L
Determining Solubility
Effect of Ion Charge
-compounds of ions with small charges tend to be soluble
-compounds of ions with large charges tend to be insoluble
-why? Increasing ion charge increases the attractive forces that hold the ions together
Effect of Ion Size
-the size of an atom is different than the size of its corresponding ion
-in general, metallic ions tend to be smaller than their corresponding neutral atoms; non-metallic ions tend to be larger than their corresponding neutral atoms
-small ions bond more closely than large ions, thus, the bond between smaller ions is stronger than