Loading in 2 Seconds...
Loading in 2 Seconds...
Ch. 4 Types of Chemical Reactions and Solution Stoichiometry. Solute. A solute is the dissolved substance in a solution. Salt in salt water. Sugar in soda drinks. Carbon dioxide in soda drinks. Solvent. A solvent is the dissolving medium in a solution. Water in salt water.
A solute is the dissolved substance in a solution.
Salt in salt water
Sugar in soda drinks
Carbon dioxide in soda drinks
A solvent is the dissolving medium in a solution.
Water in salt water
Water in soda
An electrolyte is:
A nonelectrolyte is:
Try to classify the following substances as
electrolytes or nonelectrolytes…
But why do some compounds conduct electricity in
solution while others do not…?
Na+(aq) + Cl-(aq)
Ag+(aq) + NO3-(aq)
Mg2+(aq) + 2 Cl-(aq)
2 Na+(aq) + SO42-(aq)
Al3+(aq) + 3 Cl-(aq)
The reason for this is the polar nature of
the water molecule…
Positive ions associate with the negative
end of the water dipole (oxygen).
Negative ions associate with the positive
end of the water dipole (hydrogen).
Covalent acids form ions in solution, with the
help of the water molecules.
For instance, hydrogen chloride molecules,
which are polar, give up their hydrogens to
water, forming chloride ions (Cl-) and
hydronium ions (H3O+).
Other examples of strong acids include:
Many of these weaker acids
are “organic” acids
that contain a “carboxyl”
The carboxyl group does not easily give up its
Other organic acids and their sources include:
This is an enormous group of compounds; these
are only a few examples.
Sugar (sucrose – C12H22O11),
and ethanol (ethyl alcohol – C2H5OH) do not
That is why they are nonelectrolytes!
The concentration of a solution measured in moles of solute per liter of solution.
M = mol
Problem: How many grams of sodium chloride are needed to prepare 1.50 liters of 0.500 M NaCl solution?
= 43.8 g
It is not practical to keep solutions of many different concentrations on hand, so chemists prepare more dilute solutions from a more concentrated “stock” solution.Serial Dilution
Problem: What volume of stock (11.6 M) hydrochloric acid is needed to prepare 250. mL of 3.0 M HCl solution?
MstockVstock = MdiluteVdilute
(11.6 M)(x Liters) = (3.0 M)(0.250 Liters)
x Liters = (3.0 M)(0.250 Liters)
= 0.065 L
A + BX AX + B
BX + Y BY + X
MgCl2(aq) + H2(g)
2 LiOH(aq) + H2(g)
Metals can replace other metals
provided that they are above the
metal that they are trying to
Metals above hydrogen can
replace hydrogen in acids.
Metals from sodium upward can
replace hydrogen in water
Halogens can replace other
halogens in compounds, provided
that they are above the halogen
that they are trying to replace.
2NaCl(s) + F2(g)
2NaF(s) + Cl2(g)
MgCl2(s) + Br2(g)
1. Mg + FeCl3
Fe + MgCl2
2. Sodium is added to water.
Na + H2O H2 + NaOH
3. Lithium is added to hydrochloric acid
Li + HCl H2 + LiCl
4. Zinc is added to a solution of sodium chloride
Zn + NaCl N.R.
5. Chlorine gas is bubbled into a solution of potassium iodide
Cl2 + KI I2 + KCl
6. Chlorine gas is bubbled into a solution of potassium fluoride
Cl2 + KF N. R.
The ions of two compounds exchange placesin an
aqueous solution to form two new compounds.
AX + BY AY + BX
One of the compounds formed is usually a
precipitate(an insoluble solid), an insoluble gasthat bubbles out of solution, or a molecular compound, usually water.
Double replacement (ionic) equation
Pb(NO3)2(aq) + 2KI(aq) PbI2(s) + 2KNO3(aq)
Complete ionic equation shows compounds as aqueous ions
Pb2+(aq) + 2 NO3-(aq) + 2 K+(aq) +2 I-(aq) PbI2(s) + 2K+(aq) + 2 NO3-(aq)
Net ionic equation eliminates the spectator ions
Pb2+(aq) + 2 I-(aq) PbI2(s)
1. KBr(aq) + AgNO3(aq)
AgBr(s) + KNO3(aq)
2. Silver nitrate + potassium chromate
2AgNO3(aq) + K2CrO4(aq) AgCrO4(s) + 2KNO3(aq)
3. Ammonium chloride + cobalt (II) sulfate
2NH4Cl(aq) + CoSO4(aq) (NH4)2SO4(aq) + CoCl2(aq) N.R.
4. Lithium hydroxide + sodium chromate
2LiOH(aq) + Na2CrO4(aq) 2NaOH(aq) + Li2CrO4(s)
5. Zinc acetate + cesium hydroxide
Zn(C2H3O2)2(aq) + 2CsOH(aq) Zn(OH)2(s) + 2CsC2H3O2(aq)
6. What is the net ionic equation for the rxn above?
Zn+2(aq) + OH-(aq) Zn(OH)2(s)
Na2SO3(aq) + 2HCl(aq) H2SO3(aq) + 2NaCl(aq)
H2SO3(aq) H2O(l) + SO2(g)
Na2SO3(aq) + 2HCl(aq) H2O(l) + SO2(g) + 2NaCl(aq)
2. Ammonium sulfate + sodium hydroxide
(NH4)2SO4(aq) + NaOH(aq) 2 NH4OH(aq) + Na2SO4(aq)
2 NH4OH(aq) 2 NH3(g) + H2O(l)
(NH4)2SO4(aq)+ 2NaOH(aq) 2NH3(g) + 2H2O(l) + Na2SO4(aq)
What is the net ionic equation for the reaction above?
NH4+(aq) + OH-(aq) NH3(g) + H2O(l)