Solution Chemistry Review : BRiAN CHeNG Edition Concepts :
1. Solution intro :
A.definitions : solute, solvent, homogeneous, saturated B. meaning of dissolving :
C.Solubilities of various substances a. Solids, liquids & gases
b. Ionic, molecular & hydrogen compounds 2. Concentration & concentration units
A.molarity : Main unit
B. other units : % by volume, % by mass, ppm C.manipulation of the concentration equation 3. How to make a solution from solid
Lab procedure :
4. How to dilute a solution from solution A.Dilution equation
B. Lab procedure 5. Dissociation :
A.dissociation process : explanation B. Types & properties of solutions :
a. Types of solution ( NI, NM, A & B ) b. Properties of solutions
C.Major species in solutions
D.Method of representing dissociation : dissociation equation a. 3 major emphasis of dissociation equation
b. writing dissociation equation E. Dissociation calculations
a. calculate [ ions ] & solution b. pH & pOH
6. Writing balanced equations in solution A.types of balanced equations in solution B. ionic equations
7. Stoichiometry A.gravimetric stoich B. gas stoich
C.solution stoich
D.Limiting reagent stoich E. % yield
1. Solutions are mixtures of solute dissolved in solvent A.Definitions :
a. solute is the substance dissolved
solvent is the chemical dissolving the solute
a. a solution must be a homogeneous mixture ( or evenly mixed )
b. a saturated solution is a solution in which no more solute can be dissolved
since a saturated solution could be heated and more solute can be dissolved in it after heating, therefore a saturated solution must be described along with a temperature at which saturation occurs e.g a saturated sugar solution at 25oC
B. The dissolving process is complex to explain. The simplest explanation would mean the distribution of the solute particles evenly amongst the solvent particles such that every part of the solution has just as many solute particles as solvent particles ( therefore forming an homogeneous solution ). The dissolving process always involved the breaking apart of bonding in solute particles and solvent particles so that these particles can be evenly distributed amongst each other. New bonding between solute-solvent particles are formed
C.Solubilities of various substances in water
a. The solubilities of solid solute is enhanced in hotter temperature than in cooler
temperature. The hotter temperature generally increased the break down of chemical bonding in solute and facilitates the faster redistribution of particles
Gaseous solutes have low solubility in water. The solubilities of gaseous solute is further decreased in hotter temperature than in cooler temperature. At warmer temperature, the gaseous solute particles have higher energy than the energies of the new solute-solvent bonds and can therefore escape more easily. Gaseous solutes are generally more soluble in colder temperature and under great pressure.
b. The solubility of ionic substances ( always solids at STP ) are given in the periodic table. Polar molecular substances will dissolve more readily in polar water than non-polar
substances. ( like dissolves like )
All hydrogen compounds are soluble in water. 2. Concentration & concentration units
Concentration is the ratio derived by comparing the quantity of solute against the quantity of the solution or solvent.
A. The main concentration unit in Chemistry 20 is Molarity ( or mol/L )
A 1 molar solution means 1 mole of solute was dissolved in water to make 1 L solution A 2 molar solution means 1 mole of solute was dissolved in water to make 1 L solution
B. Other concentration units a. % by mass :
A 1% by mass solution means 1 g of solute was dissolved to make 100 mL of solution b. % by volume :
A 1% by volume solution means 1 mL of solute was dissolved to make 100 mL of solution c. ppm : ( parts per million )
3. To make a solution from solid solute involved A.procedure : ( CADTRASM )
a. calculate mass of solute required b. acquire solute by weighing
c. dissolve mass in ½ volume of solvent d. transfer solution into volumetric flask e. rinse beaker and pour rinse water into flask
f. add water to gradated mark with meniscus finder and eye dropper g. stopper and mix to achieve homogeneous state
B. equation required :
the calculation involved manipulating 2 equations
4. To dilute a solution from stock solution involved the following : A.dilution procedure : ( CATASM )
a. Calcalate volume of concentrated solution required to dilute b. Acquire solution with pipet
c. Transfer solution into volumetric flask d. Add water to gradated mark
e. Stopper and Mix
5. Dissociation :
A.dissociation process : explanation
When soluble ionic substances are dissolved, the polar water molecules can form weak bonds with the cations and the anions of the ionic compound. These weak bonds will eventually break apart the ionic compound into its composite ions.
Dissociation is defined as the breaking apart of soluble substances by water into its composite ions.
Strong acids can totally dissociate in water to give H+ion and anions
B. Types & properties of solution :
Liquid water is a non-electrolyte and it will not change the color of litmus paper.
After dissolving soluble ionic compound in water, the solution becomes an electrolyte. This is because the ionic compound dissociates in water to give ions and the presence of ions in solution will cause the solution to become electrolytic. Ionic solutions will not change the color of litmus. Ionic solutions are generally called Neutral ionic solutions
Molecular substances will not be able to dissociate in water. The resultant solution will be a non-electrolyte and cannot change the color of litmus ( Neutral molecular solution ) Strong acids dissociate in water will give hydrogen ions and anions. The solution is an
electrolyte and will also change litmus paper red. ( Acidic solution )
Other properties of an acidic solution : low pH, taste sour, react with active metal to give gaseous products, neutralize base
Strong bases ( ionic compounds with OH- ) will dissociate in water to give cations and OH
-ions. The solution will change litmus paper blue ( Basic solution )
Other properties of basic solution : feels slippery, taste bitter, high pH, neutralize bases. Various ionic solutions when heated strongest will give distinctive color ( data table ) e.g Li+
(aq) will give red flame color
Cu2+
(aq) will give green flame color
C.Major species in solutions
The major species in neutral ionic solution = cations, anions and water The major species in neutral molecular solution = solute molecules and water The major species in acidic solution = H+, anions and water
D.Method of representing dissociation : dissociation equation
Dissociation equations are used to describe the dissociation phenomenon. There are 3 major emphasis when writing dissociation equation.
- charge of the ions must be correctly written - states must be correctly written
- equation must be balanced
E. Dissociation calculations
The mole unit and the concentration unit ( mol/L ) can be applied to a dissociation equation. e.g. 1 Na3PO4(aq) - - > 3 Na+(aq) + 1 PO43-(aq) , this dissociation equation can be read as :
1 mol of sodium phosphate dissolved in water to give 3 mol of sodium ions and 1 mol of phosphate ion or 1 mol/L sodium phosphate solution will give 3 mol/L sodium ions and 1 mol/L phosphate ion
A 0.570 mol/L sodium of Na3PO4(aq) will give 1.71 mol/L Na+(aq) ion and 0.570 mol/L PO43-(aq) ion
The dissociation of sodium phosphate in water can be represented as follows : Na3PO4(s) - - > Na3PO4(aq) - - > 3 Na+(aq) + 1 PO43-(aq)
Or simply written as :
Na3PO4(s) - - - > 3 Na+(aq) + 1 PO43-(aq)
Dissolving process
Dissociating process
What are the concentrations of ions in solution if 5.00g of Na3PO4(s) is dissolved in
water to make a 600 mL solution ?
a.
b. 1 Na3PO4(aq) - - > 3 Na+(aq) + 1 PO43-(aq)
0.0508 mol/L will give 3 ( 0.0508 ) or 0.152 mol/L Na+
(aq) ion and 0.0508 mol/L PO43-(aq) ion
pH = - log [ H+ (aq) ]
pOH = - log [ OH -(aq) ]
[ OH
-(aq) ] = 10-pOH
[ H+
(aq) ] = 10-pH
6. Writing balanced equations in solution A.types of balanced equation in solution
There are two types of balanced equation in solution a. precipitation reactions b. neutralization reactions
precipitation reaction involved the reaction between an element with a solution and will always give a new solution and a precipitate or a gaseous element.
e.g. 2 Na(s) + 2 HCl(aq) - - > 2 NaCl(aq) + 1 H2(g) [ gaseous element ]
2 Al(s) + 3 Cu(NO3)2(aq) - - > 2 Al(NO3)3(aq) + 3 Cu(s) [ precipitate ]
neutralization reaction involved the reaction between an acidic and basic solution and will always give a new solution and water(l).
e.g. 1 H2SO4(aq) + 2 NaOH(aq) - - > 1 Na2SO4(aq) + 2 HOH(l)
2 HCl(aq) + 1 Ba(OH)2(aq) - - > 1 BaCl2(aq) + 2 HOH(l)
B. ionic equations : non-ionic, total ionic and net-ionic equations
There are 3 types of ionic equations : non-ionic, total ionic and net-ionic equation Non-ionic equation ( balanced equation with states indicated )
2 Al(s) + 3 Cu(NO3)2(aq) - - > 2 Al(NO3)3(aq) + 3 Cu(s)
total ionic equation : ( shows major species in each solution )
2 Al(s) + 3 Cu2+(aq) + 6 NO3-(aq) - - > 2 Al3+(aq) + 6 NO3-(aq) + 3 Cu(s)
net-ionic equation : ( shows only changes occurring in elements or ions ) 2 Al(s) + 3 Cu2+(aq) - - > 2 Al3+(aq) + 3 Cu(s)
Alo
(s) changed into Al3+(aq) by losing 3 e- [ Al - - > Al3+ + 3 e- ]
Cu2+
(aq) changed into Cuo(s) by gaining 2 e- [ Cu2+ + 2 e- - - > Cu ]
Write ionic equations for the following :
a. HCl(aq) + Ba(OH)2(aq) b AgNO3(aq) + NaCl(aq)
2 HCl(aq) + 1 Ba(OH)2(aq) - - > 1 BaCl2(aq) + 2 HOH(l)
2 H+
(aq) + 2 Cl-(aq) + 1 Ba2+(aq) + 2 OH-(aq) - - > 1 Ba2+(aq) + 2 Cl-(aq) + 2 HOH(l)
2 H+
(aq) + 2 OH-(aq) - - > 2 HOH(l)
AgNO3(aq) + NaCl(aq) - - > AgCl(s) + NaNO3(aq)
Ag+
(aq) + NO3-(aq) + Na+(aq) + Cl-(aq) - - > AgCl(s) + Na+(aq) + NO3-(aq)
Ag+
7. Stoichiometry
Stoichiometric calculations types of questions will always gives 1 quantity of chemical and asked to predict quantity of another chemical.
The stoichiometric process is as follows : - write balanced chemical equation
- list below equation, what is given and what is asked for - change given to moles ( if necessary )
- convert moles of given to moles of required
- change required mole calculated to other units ( if necessary )
Three ways to convert given to moles
What mass of Al(s) will react with 500 mL of a 0.250 mol/L Cu(NO3)2(aq) ?
2 Al(s) + 3 Cu(NO3)2(aq) - - > 2 Al(NO3)3(aq) + 3 Cu(s)
? g 500 mL 0.250 mol/L
n of Cu(NO3)2(aq) = CV = 0.250 mol/L x 0.500 L = 0.125 mol
n of Al(s) = 2/3 x 0.125 mol = 0.0833 mol
m of Al(s) = 0.0833 mol x 26.98 g/mol = 2.25 g
What is the concentration of a 600 mL HCl(aq) that can react with Na(s) in order to release
300 mL of gas at 101 kPa and 80oC ?
2 Na(s) + 2 HCl(aq) - - > 2 NaCl(aq) + 1 H2(g)
600 mL 300 mL
? C 101 kPa & 80oC
n of H2(g) =
n of HCl(aq) =
[ HCl(aq) ] =
b. Titration & lab procedure :
The purpose of titration is to collect data for stochiometric calculation. Titration is defined as the progressive addition of 1 reagent into another
Procedure : refer to page 536 of Nelson text Data table used for titration
Equivalence point = the point when equal amount ( moles ) of reactants had been reacted End point = the point when the indicator changes color to signify the end of the titration 8. Excess stoichiometry
A special type of stoichiometric calculation involved 2 given quantities and asked to find a third One of the 2 given will be in excess and the other given will be the limiting reagent.
Limiting reagent limits the amount of product produced and should be used for calculation
Procedure :
- write balanced equation
- list below equation both given and required - change both given to moles
- calculate which given is the limiting reagent
- using the limiting reagent to calculate mole required - change mole required to other units
Titration 1 Titration 2 Titration 3 Titration 4 Volume of unknown used ( mL )
Final buret reading ( mL ) Initial buret reading ( mL ) Volume used ( mL ) Color of indicator
What mass of water can be produced if 5.00 g of H2SO4 and 5.00 g of NaOH is reacted ?
1 H2SO4(aq) + 2 NaOH(aq) - - > 2 HOH(l) + 1 Na2SO4(aq)
5.00g 5.00g ? g
0.0510 mol 0.125 mol
0.0510 mol of H2SO4 will need 0.102 mol
of NaOH and there are more than that of
NaOH, therefore 0.0510 mol of H2SO4 is the limiting reagent and should be used for
this calculation
n of HOH =
Review exercise : 1. Concentration units
A.molarity ( mol/L )
do the following calculations :
a. what is the concentration of solution if 0.25 mol of NaCl is dissolved in water to make a 600 mL solution ?
b. what volume of solution is required to dissolve 4.0 mol of NaCl to make a 1.5 mol/L solution ?
c. what amount ( mol ) of NaCl is required to make 500 mL of a 0.475 mol/L solution ? B.% W/V
a. what is % W/V of solution if 40 g of Li2S(s) is dissolved to make a 500 mL solution ?
b. what mass of Li2S(s) is needed to make 850 mL of a 3.6 % W/V solution ?
c. what volume of solution is required to dissolve 30 g of Li2S(s) in order to make a 7.25 %
W/V solution ? C.% V/V
a. what is the % V/V of solution if 35 mL of C2H5OH(l) is dissolved to make a 1.20 L
solution?
b. What volume of solution is required to dissolve 25 mL of C2H5OH(l) in order to make a
6.5 % V/V solution ?
c. What volume of C2H5OH(l) must be dissolved in order to make 450 mL of a 7.5 % V/V
solution ? D.Ppm
a. Calculate ppm of solution if 5.0 g of KOH(s) is dissolved to make a 4000000 mL solution
b. What mass of KOH(s) must be dissolve in 5.00 L of solution if the concentration of
solution is 15 ppm ?
c. What mass of KOH(s) must be dissolve in 4000 L of solution if the concentration of
solution is 400 ppm ?
d. What mass of KOH(s) must be dissolved in 8000000 mL of solution if the concentration of
solution is 50 ppm ?
e. What volume of solution is required to dissolve 40 g of KOH(s) in order to make a 300
ppm solution ? 2. making solutions
A.calculations
a. what is molarity of solution if 5.00 g of Ba(NO3)2(s) is dissolved to make a 100 mL
solution
b. what mass of Ba(NO3)2(s) is required to make 400 mL of a 0.250 mol/L solution ?
c. what volume of solution is needed to dissolve 3.00 g of Ba(NO3)2(s) to make a 1.25 mol/L
solution ? B.making solution
a. what is the name of the accurate glass container used to make 100 mL solution ?
b. name the two pieces of equipment required to bring the volume up to the gradated mark of this container ?
c. identify the acronym describing the process used to make a solution
3. diluting solutions A.calculations
a. what volume of 0.450 mol/L solution can be made by diluting 50 mL of a 1.50 mol/L? b. what volume of water is used to dilute 25.0 mL of a 2.6 mol/L solution in order to make a
1.0 mol/L solution ? B.making dilutions
a. what is name of accurate glassware used to transfer solution ?
b. briefly describe how to make 100 mL of a 0.150 mol/L solution from 1.50 mol/L solution. ( show calculation )
c. what is the acronym used to describe how to dilute a solution ? 4. dissociation process
A.identifying major species
list major species found if each of the following is stirred into a beaker of water
B.writing dissociation equations and calculate concentration of ions
for each of the following, a. write dissociation equation b. calculate the concentration of either the ions in solution or the concentration of the solution
a. 0.260 mol/L solution of sodium carbonate b. 0.510 mol/L of ammonium phosphate solution c. 100 mL of a 0.250 mol/L aluminium nitrate solution
d. a strontium nitrate solution has a nitrate ion concentration = 0.460 mol/L e. an sodium sulfide solution has a sulfite ion concentration = 0.260 mol/L C.calculating ion concentrations from solid
a. what are the concentrations of each ion if 5.00 g of sodium sulfide is dissolved to make a 500 mL solution ?
b. what mass of barium acetate must be dissolved in order to make 300 mL of solution which has an acetate ion concentration of 0.850 mol/L ?
D.calculating pH and pOH
a. what is the pH of solution if 14 g of hydrogen iodide is dissolved to make a 600 mL solution ?
b. what mass of strontium hydroxide must be dissolved in order to make 500 mL of solution which has a pOH of 1.50 ?
formula Major species in solution formula Major species in solution
Na2CO3 Ag2S
C6H12O6 Ba(OH)2
CaCO3 C2H5OH
H2SO4 NH4ClO4
Au Br2
E.characteristic of solutions
a. under what conditions can we dissolve more NaCl(s) into an already saturated solution ?
b. under what conditions can we dissolve CO2(g) in water ?
c. what is the color of each of the following solution ?
i. a solution containing permanganate ions ? ________ ii. a solution containing Fe2+
(aq) ions ? _________
iii. a solution containing Co2+
(aq) ions ? _________
iv. a solution containing Chromium III ions ? ____________ d. What is the flame color of solution
i. a lithium nitrate solution ? _________ ii. a copper II nitrate solution ? ________ iii. a lead II nitrate solution ? _______
e. Give 5 physical characteristics of each of the following solution i. acidic solution ii. Basic solution
Review exercise ANSWeRS: 5. Concentration units
A.molarity ( mol/L )
do the following calculations :
a. what is the concentration of solution if 0.25 mol of NaCl is dissolved in water to make a 600 mL solution ? 0.42M
b. what volume of solution is required to dissolve 4.0 mol of NaCl to make a 1.5 mol/L solution ? 2.7L
c. what amount ( mol ) of NaCl is required to make 500 mL of a 0.475 mol/L solution ? 13.9g
B.% W/V
a. what is % W/V of solution if 40 g of Li2S(s) is dissolved to make a 500 mL solution ?
8%w/v
b. what mass of Li2S(s) is needed to make 850 mL of a 3.6 % W/V solution ?30.6g
c. what volume of solution is required to dissolve 30 g of Li2S(s) in order to make a 7.25 %
W/V solution ? 0.41L C.% V/V
a. what is the % V/V of solution if 35 mL of C2H5OH(l) is dissolved to make a 1.20 L
solution? 2.92
b. What volume of solution is required to dissolve 25 mL of C2H5OH(l) in order to make a
6.5 % V/V solution ?0.38L
c. What volume of C2H5OH(l) must be dissolved in order to make 450 mL of a 7.5 % V/V
solution ?34mL D.Ppm
a. Calculate ppm of solution if 5.0 g of KOH(s) is dissolved to make a 4000000 mL solution
1.25ppm
b. What mass of KOH(s) must be dissolve in 5.00 L of solution if the concentration of
solution is 15 ppm ?75mg
c. What mass of KOH(s) must be dissolve in 4000 L of solution if the concentration of
solution is 400 ppm ? 1600g
d. What mass of KOH(s) must be dissolved in 8000000 mL of solution if the concentration of
solution is 50 ppm ? 400g
e. What volume of solution is required to dissolve 40 g of KOH(s) in order to
make a 300 ppm solution ?1333.3L 6. making solutions
a. what is molarity of solution if 5.00 g of Ba(NO3)2(s) is dissolved to make a 100 mL
solution 0.191M
b. what mass of Ba(NO3)2(s) is required to make 400 mL of a 0.250 mol/L solution ? 26.1g
c. what volume of solution is needed to dissolve 3.00 g of Ba(NO3)2(s) to make a 1.25 mol/L
solution ? 9.81mL B.making solution
a. what is the name of the accurate glass container used to make 100 mL solution ? volumetric flask
b. name the two pieces of equipment required to bring the volume up to the gradated mark of this container ? eye dropper and meniscus finder
c. identify the acronym describing the process used to make a solution CADTRASM d. briefly describe the process required to make 100 mL of a 0.55 mol/L solution of a
KNO3(s) ( show calculations )C=5.01g ADTRASM
7. diluting solutions A.calculations
a. what volume of 0.450 mol/L solution can be made by diluting 50 mL of a 1.50 mol/L? 166mL
b. what volume of water is used to dilute 25.0 mL of a 2.6 mol/L solution in order to make a 1.0 mol/L solution ? Final volume is 65mL so H20 added is 40mL
B.making dilutions
a. what is name of accurate glassware used to transfer solution ? pipette
b. briefly describe how to make 100 mL of a 0.150 mol/L solution from 1.50 mol/L solution. ( show calculation ) 10.0mL
c. what is the acronym used to describe how to dilute a solution ?CATASM 8. dissociation process
A.identifying major species
list major species found if each of the following is stirred into a beaker of water
B.writing dissociation equations and calculate concentration of ions
for each of the following, a. write dissociation equation b. calculate the concentration of either the ions in solution or the concentration of the solution
a. 0.260 mol/L solution of sodium carbonate Na2CO3 2Na+ + CO32- [Na]=0.52M [CO32-]=.26M
b. 0.510 mol/L of ammonium phosphate solution (NH4)3PO4 NH4+ + PO43- [NH4+ ]=1.53M [PO43-]=0.510M
c. 100 mL of a 0.250 mol/L aluminium nitrate solution Al(NO3)3 Al3+ + 3NO3 -[Al3+ ]= 0.250M [NO3-]= 0.75M
formula Major species in solution formula Major species in solution Na2CO3 Na+) CO3- H20 Ag2S Ag2S(s) H20(l)
C6H12O6 C6H12O6(aq) H20(l) Ba(OH)2 Ba(OH)2(s) H20(l)
CaCO3 CaCO3(aq) H20(l) C2H5OH C2H5OH(aq) H20(l)
H2SO4 H+ HSO4- H20(l) NH4ClO4 NH4+ ClO4- H20(l)
Au Au(s) H20(l) Br2 Br2(l) H20(l)
d. a strontium nitrate solution has a nitrate ion concentration = 0.460 mol/L
Sr(NO3)2 Sr2+ + 2NO3- [Sr2+ ]=0.22M [Sr(NO3)2]=0.22M e. an sodium sulfide solution has a sulfite ion concentration = 0.260 mol/L
Na2S2Na+ + S2- [Na+]=0.13M [Na2S]= 0.13M C.calculating ion concentrations from solid
a. what are the concentrations of each ion if 5.00 g of sodium sulfide is dissolved to make a 500 mL solution ? [Na+]=0.229 [S2-]=0.115
b. what mass of barium acetate must be dissolved in order to make 300 mL of solution which has an acetate ion concentration of 0.850 mol/L ?33.2g
D.calculating pH and pOH
a. what is the pH of solution if 14 g of hydrogen iodide is dissolved to make a 600 mL solution ? 0.74
b. what mass of strontium hydroxide must be dissolved in order to make 500 mL of solution which has a pOH of 1.50 ? 0.96g
E.characteristic of solutions
a. under what conditions can we dissolve more NaCl(s) into an already saturated solution ?
heat it up
b. under what conditions can we dissolve CO2(g) in water ? cool down the solution or
increase the pressure of the CO2 above the solution
c. what is the color of each of the following solution ? j. a solution containing permanganate ions ? purple v. a solution containing Fe2+
(aq) ions ? lime green
vi. a solution containing Co2+
(aq) ions ? red
vii. a solution containing Chromium III ions ? blue-green d. What is the flame color of solution
j. a lithium nitrate solution ? red
iv. a copper II nitrate solution ? blue-green v. a lead II nitrate solution ? blue-white
e. Give 5 physical characteristics of each of the following solution
i. acidic solution pH<7, conduct electricity, taste sour, reacts with metals to produce hydrogen gas,
j. ii. Basic solution pH>7, feel slippery, conducts electricity, neutralizes acids, taste bitter, hurts when you rub it in your eyes
f. Give 2 physical characteristics of each of the following solution i. neutral ionic solution pH=7, conducts electricity
