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UNIT 4 – Solutions and Solubility
Chapter 8 Solutions and Concentration
Types of Solutions
The simplest solutions contain 2 substances:
1. SOLVENT
o
o
2. SOLUTE
o
When solute dissolves in a solvent, ________________________________ and the
substances can be ________________________________________________________.
Solutions are ______________________ mixtures and can be _____________________.
Steel –
Kool-aid –
Air –
Most common solutions are _________________
The most common of these are _________________________ where ___________ is the
_______________________
Many substances dissolve easily ___________________________. These substances are
said to be ___________________ with each other.
Ex.
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Some substances _______________ dissolve in each other. These are said to be
___________________________. Ex.
SOLUBILITY is a measurement of __________________________________________
____________________________________________________________________.
Ex. The solubility of NaCl in H2O at ___________________________________.
A ________________________________ SOLUTION is a solution that
________________________________. If we try to add ______________________ of
NaCl to 100mL of H2O, it will ______________________________
An __________________________ SOLUTION is a solution ____________________.
Solutes described as _________________ have a solubility of _____________________
Solutes described as _________________ have a solubility of _____________________
Solutes described as __________________________________ have a solubility of
____________________________________________________
Factors Affecting Rate of Dissolving and Solubility
The ____________________________________________ measures how fast a
______________________________________. This rate is dependent on many factors.
1. _____________________
a.
b.
2. ____________________
a.
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3. _______________________
a.
b.
The reason that one substance dissolves in another is because of ____________________
________________________________________________________________________
The forces include the attraction between:
1.
2.
3.
When the force of attraction between _______________________ particles is
____________________________ the attraction between ______________ particles a
_______________________ is formed.
The ____________________________________ between particles determines solubility
Recall the Thought Lab on pg. 288:
Iodine was insoluble in water. This means that the ______________________________
____________________________________________________. Also the force of
attraction between ________________________ (intermolecular forces) are strong.
Iodine was soluble in kerosene. The force of attraction between ___________________
____________________________________ than the attraction between
_________________________ as well as between ______________________________.
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INTERMOLECULAR FORCES
In Unit 1 you learned the difference between polar and non-polar molecules.
Recall water:
Water is polar because it appears to other molecules to have _______________
______________________________________. Molecules like this are said to have a
______________________________________.
A DIPOLE consists of ____________________________________________________.
Remember how water “sticks” to water?
This is a result of the ______________________________________________________.
These are called __________________________________________________________.
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This is a type of _________________________________________. They act between
molecules. These forces are about ______________________ as an ionic or covalent
bond (______________________________)
A special type of dipole-dipole attraction happens when __________________________
_____________________________________. Because these atoms are so
____________________________________, H gets a positive charge that is
_________________________. This leads to __________________________________.
When ________________ substance are dissolved in a ______________________ the
the _____________________________ of the ionic compound are attracted to different
___________________________. This is known as _____________________________.
In an _______________________ each cation and anion will be surrounded by _______
___________________. Each ion is said to be ___________________ and
________________________ can move freely in the solution making it an
____________________________________ (soln with the ability to conduct electricity).
__________ ionic compounds are soluble but _________________.
To predict solubility __________________________________:
Large difference – __________________________________________________
Small difference – __________________________________________________
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When _______________________________ are mixed with water, most are _________.
This is because many are _________________________. Exceptions are
______________ and _______________. Both of these form ______________ with
water.
However, ______________ covalent compounds are soluble in _____________ solvents.
In general ____________________________________________.
- _____________________________ solutes dissolve in _______________ solvents.
- ___________________ solutes dissolve in ______________________ solvents.
Some substances behave as both polar and non-polar substances. _______________ is
an example
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Factors Affecting Solubility
Don’t get confused with ________________________________________.
1. Molecule Size
- .
-
2. Temperature
-
- When a solid dissolves ________________ to break bonds between particles.
-
- This is true for __________________.
- For ___________ energy is not required so temp has ________________ on
solubility
- When ____________ dissolve in liquids they actually lose energy, so
__________________________________________________________________
3. Pressure
- Changes in pressure have __________________ on solid and liquid solubility
- The solubility of a gas is __________________________________________
______________________________________________________________
- For example in a 2L pop bottle the pressure of CO2 is ___________________.
Solubility of CO2 in the ____________________. When you open the bottle,
the pressure of CO2 ________________________________, solubility
______________________________________________________________!
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Concentration of Solutions
Mass/Volume Percent
Chemists often express the concentration of an _____________________________ as
the MASS ____________________________________________________________.
It is usually expressed as a _________________________________
It can also be referred to as __________________________________
This is different from solubility. (mass per unit volume)
Ex 1. A pharmacist adds 4.0 mL of H2O to 8.00g of powdered drug. The final volume
of the solution is 6.00mL. What is the percent (m/v) of the solution? What is the
concentration in g/100mL?
Ex 2. Trisodium phosphate (TSP) is used as a cleaner to prep surfaces before painting.
The recommended concentration of TSP is 1.7% (m/v). What mass of TSP is required to
make 4.0L of solution?
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Mass / Mass Percent
The __________ of a solution containing a solid solute dissolved in a liquid solvent can
be expressed as the _________________________ and is called
________________________________________ (you might also see it as w/w percent)
Many metal alloys have their concentration expressed as
percent (m/m)
Ex1. Dental amalgam used as dental fillings is made by mixing mercury, silver and tin.
If a sample of a dental filling has a mass of 1.35g and after heating the solution you
obtain 0.4725g of silver, what is the mass/mass percent of silver in dental amalgam and
how much would you need to make 100g of dental amalgam?
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Volume / Volume Percent
When mixing 2 liquids it is common to express _______________________________.
This may also be referred to as ______________________________________________
Ex 1. Rubbing alcohol is an antiseptic. It is sold as 70% (v/v). What volume of
isopropyl alcohol is used to make a 500ml bottle?
Parts per million and Parts per billion
____________________________ are usually used to express
_______________________ in the )___________________________________. Both
are usually mass/mass relationships.
For (ppb) substitute 106 with 10
9
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Ex1. A toxic fungus that grows on peanuts can cause liver damage in humans. The
maximum amount of toxin allowed is 25ppb. If 20t of peanuts are to be made into peanut
butter, what is the maximum mass of toxin permitted?
Ex 2. Mercury is toxic in humans if more than 20mg has accumulated.
i.Express this in ppm for a 75kg person
ii.Express this in ppb
iii.Express this in (m/m) percent
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Molar Concentration
This is the concentration used in chemistry
____________________________ is the ______________________________________
Molar [ ] can be referred to as ________________________
This formula can be shortened to:
Units are ___________________________
The advantage of using molar concentrations is that it is related to the # of particles in the
solution. None of the other concentrations are.
Ex1. A saline solution contains 0.90g of solute dissolved in 100mL of solution. What is
the molar concentration?
Ex 2. Formalin is a solution containing formaldehyde, CH2O, used to preserve biological
specimens. What mass of CH2O is required to prepare 2.25L of 10.5M solution?
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Preparing Solutions
A soln of known concentration is referred to as a _______________________________.
There are 2 ways to make a standard solution:
1.
2.
To prepare a standard solution you use a ___________________________________.
These flasks are able to measure to _______________________
Diluting a Solution
You can also make a less concentrated standard solution by adding a measured amount of
extra solvent to a solution with a known concentration.
Ex. 1 You must make 2.0L of 0.10M sulfuric acid. This acid is sold as 18M. How much
of the standard solution do you need to make the new solution?
There is an easier way. ____________________________________________________
_______________________________________________________________________
_______________________________________________________________________
This formula can be used to solve basic dilution questions.
Try the above question again.
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Chapter 9 Aqueous Solutions
Making Predictions about solubility
Recall:
Soluble Partly of Slightly Soluble Insoluble
Factors that affect the solubility of Ionic Substances
1. _________________________
Ions with small _______________________________________________.
Ions with large ________________________________________________.
Increasing the charge _____________________________________________.
For example: ________________ tend to be insoluble, __________ salts soluble.
2. _____________________________
Compounds with __________________________________________ than
compounds with __________________________.
___________________ ions ____________ more closely than ______________.
The above can allow you to make some predictions about solubility. What do think about
sulfides (compounds with S2-
)?
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There are many interrelated factors affecting solubility, and _____________________
must be _____________________________________________________ for solubility.
Chemists rely on published data to determine ________ a substance is soluble,
____________ soluble it is, and it’s _______________________ to other similar
compounds.
There are however ________________________________________________________.
Guideline Cation
Anion Result Exceptions
1
2
3
4
5
To use this table remember that ______________________________________________
________________________________________________________________________
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Reactions in Aqueous Solutions
When you mix 2 aqueous ionic compounds together 2 things can happen:
1.
2.
If a chemical reaction occurs you may observe:
1.
2.
3.
1.___________________
To predict the formation of a __________________________________, use your
_______________________________________________________________ and your
knowledge of _________________________________________ to predict the out come.
Ex. Will the following reaction produce a precipitate?
Pb(NO3)2 + KI
2. _________________________________________
Double displacement reactions can result in the production of the following
________________________________________________________________________
__________________ Gas
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- ________________ (alkali metal + H) react with water to produce
_______________.
_____________ Gas
- ________________ react with certain acids to produce ____________.
_____________ Gas
- Some reactions produce a product that ____________________________.
_____________ Gas
- __________________________ to produce carbonic acid, which
decomposes into _______________________________.
__________________ gas
- _____________________ react with bases to produce _____________.
3. _____________________
Neutralization reactions between __________________________,
____________________ and acids, and ________________________ and bases all
result in the formation of water.
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IONIC EQUATIONS
Imagine mixing aqueous solutions of NaCl and AgNO3.
You would predict that:
The other ions are not really important to the overall result.
We call these ions _______________________________.
The chemical equation for this reaction is:
This reactions shows the reactants and products as _________________________. In
reality though the compounds ______________________________so chemists usually
refer to the _________________________________________________________.
Now you can see the _____________________________. Because they appear on
_______________________________________________________________________.
This is called the ______________________________________.
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Copy the guidelines for writing Net Ionic Equations from pg. 342.
Ex. 1 Aqueous solutions of sodium sulphide and iron (III) sulphate are mixed. Identify
the spectator ions and write the balanced net ionic equation.
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Stoichiometry in Solution Chemistry
These problems are solved the same way as the previous stoichiometry problems you did
with the addition of a couple of items:
1.
2.
Ex. 1 Calculate the [chloride ions] in mol/L the following solutions:
a. 19.8g of potassium chloride dissolved in 100mL of solution.
b. 26.5g of calcium chloride in 150mL of solution
c. a mixture of the two solutions in a. and b. assuming the volumes are
additive.
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Ex 2. Rhubarb leaves are poisonous because of the oxalate C2O42-
ions present in them.
If you tested 238.6 g of leaves by adding calcium chloride to precipitate calcium oxalate
and extracted 0.556g of calcium oxalate, what was the mass percent of oxalate ions in the
leaves?
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Ex. 3 Solutions containing silver ions are often mixed with chloride ions to precipitate
silver chloride. What is the minimum volume of 0.25mol/L magnesium chloride needed
to precipitate all the silver ions in 60mL of 0.30 mol/L silver nitrate?
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Ex 4. When Hg is used in industry it must be removed from all waste water, because it is
toxic. Suppose 50.00mL of 0.045mol/L sodium sulphide is added to 101.4mL of 0.05M
mercury (II) nitrate. What mass of mercury (II) sulphide precipitates?
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Ex 5. Silver chromate Ag2CrO4 is insoluble. Calculate the mass of silver chromate that
forms when 50.0mL of 0.25M silver nitrate reacts with 25.0mL of 0.30M sodium
chromate.
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Chapter 10
Acids and Bases
Acids and bases are common products.
Citrus Fruits
Dairy products
Soft drinks
Underarm odour
Oven cleaner
Baking Soda
Glass Cleaner
Acids and bases are groups of chemicals that share similar physical and or chemical
properties
Properties Acid Bases
Taste
Indicators
Feel
Form ions in solution
Conduct electricity
React with metal
React with carbonates
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Theories of Acids and Bases
Since their discovery, people have tried to describe what makes an acid an acid and a
base a base.
Arrhenius Theory of Acids and Bases
In the late 19th
century the Swedish chemist named Svanté Arrhenius discovered that
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
Arrhenius published his theory:
- ____________________________________________________________
____________________________________________________________
- ____________________________________________________________
____________________________________________________________
According to Arrhenius’ theory, acids (which always contain an H+ ion) _____________
_______________________________ and bases (which always contain an OH- ion)
_________________________________________________________.
Arrhenius theory is useful if you are interested in ________________________________
________________________________________________________________________
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However there are some problems:
1. The ion responsible for making an acid is H+. This happens when acids are added
to water. But what happens between ___________________________________?
In the 20th
century, chemists discovered that H+
ions
_____________________________________ but are always ______________.
A hydrated H+ ion is called a __________________________________________
2. Consider the base NH3. _____________________________________________
_________________________________________________________________.
3. It is limited to acid-base reactions _________________________.
Brønsted-Lowry Theory of Acids and Bases
In 1923 two chemists (independently) came up with a new theory, which helped explain
the limitations of the Arrhenius theory.
There theory stated:
- ____________________________________________________________
- ____________________________________________________________
Brønsted-Lowry acids also contain an _____________. This means all ______________
________________________________________________________________________
But, ___________________________________________________________________.
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According to Brønsted-Lowry theory there is only one requirement for an acid-base
reaction:
________________________________________________________________________
________________________________________________________________________
This means that any substance can be an acid as long as __________________________
_______________________________________________________________________.
The reverse is true as well.
Consider HCl added to water
Two molecules or ions that are related by the transfer of a proton (H+) are called a
___________________________________________________________________
The ________________________________ of an acid is the particle that remains when a
proton ______________________ from the acid.
The ________________________________ of a base is the particle that results when the
base _________________________ the proton from the acid.
Ex1. Hydrogen bromide is a gas that is soluble in water. The resulting solution is called
hydrobromic acid. Identify the conjugate acid-base pairs.
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Ex.2 Ammonia is soluble in water. It forms a basic solution commonly used in window
cleaners. Identify the conjugate acid-base pairs in the reaction between ammonia and
water.
Ex 3. Identify the conjugate acid-base pairs as well as the acid, base and conjugate acid
and base.
HCOOH + CN- HCOO
- + HCN
Strong and Weak Acids and Bases
ACIDS
In a STRONG ACID the acid _______________________________________________.
HCl is a strong acid. All the HCl molecules ____________________________________
________________________________________________________________________
________________________________________________________________________
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Strong acids include:
In a WEAK ACID the acid _________________________________________________.
On average about 1%
________________________________________________________________________
________________________________________________________________________
Most acids are weak.
Acetic Acid is an example of a weak acid
The arrows mean this reaction is ____________________. Molecules of acetic acid
dissociate just as _________________________________________________________
to produce acetic acid molecules.
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Mono, Di, Tri – Protic Acids
Some acids contain only a ____________________________ that can dissociate. These
are called _________________________________.
Many acids contain _______________________. These are referred to as
_______________________. Sulphuric acid is an example
The first dissociation is complete. The remaining hydrogen sulphate ion is a __________
________________________________________________________________________
Some acids are _____________________________________________.
The more dissociations that take place ________________________________________.
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Bases
Strong and weak bases follow the same rules as the acids above.
Strong Bases
Naming Acids and Their Anions
There are 2 kinds of acids: Binary Acids and Oxoacids (oxyacids).
Binary Acids are composed of 2 elements: ______________________________.
They have the general formula HX
To name:
1.
2.
3.
4.
Oxoacids are formed from a ____________________ that contains _________________
______________________________________________________
To name:
1.
2.
3.
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pH
pH stands for the “power of hydrogen”.
Think about water. All aqueous solutions contain ions, even pure water.
On average at 25oC on 2 water molecules in a billion are dissociated at any time. Since
ions in solution are required to conduct electricity, pure water is not a conductor.
In neutral water the [H3O+] at 25
oC is 1.0x10
-7 mol/L
Therefore the [OH-] is also 1.0x10
-7 mol/L
Compared with neutral water acidic solutions contain [] of hydronium ions. Basic
solutions contain [] of hydronium.
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The pH scale – Powers of 10
Concentrations of hydronium ions ranges from about
_______________________________________________________________________.
The big range and negative powers of 10 are not convenient to work with.
The Danish biochemist Søren Sørensen came up with a method to measure [ ] using a
logarithmic scale.
The logarithm of a number is the power to which you must raise ____________________
________________________________________________________________________
Sørensen defined pH as ___________________________________________________
So water has a pH of
Ex 1. Orange Juice has a [hydronium ions] of 2.5x10-4
. What is the pH of orange juice?
Ex 2. Household ammonia has a pH of 11.9. What is the concentration of [H3O+]?
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Neutralization Reactions
There are many types of acids and bases and being able to predict the results of reactions
between them is important.
The reaction between _____________________________________________________.
SALT is an ______________________________________________________________
For example sodium nitrate is used to slow the rate of bacterial growth in foods. It can be
made by mixing nitric acid with sodium hydroxide.
The balanced chemical equations shows:
-
-
For most neutralization reactions there is ______________________________ that a
reaction is occurring. To see this we use ______________________________________.
Most indicators are _____________________________________________, where the
the _____________________________________ is one colour and its
_______________________________ a different colour.
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Phenolphthalein is an example_______________________________________________
Calculations involving Neutralization Reactions
Ex 1. You have 25.00mL of NaOH left over from your experiment and you want to
neutralize it before dumping it in the sink. You find that it takes 19.75mL of HCl to
neutralize it. What was the [ HCl ]?
Ex. 2 What volume of 0.50M sulfuric acid is needed to react completely with 45mL of
0.85M calcium hydroxide?
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In a titration experiment, 25.00mL of an aqueous solution of NaOH was required to
neutralize 55.00mL of 0.010M HCl. What was the molar concentration of NaOH?
Read pg. 399 to 401 and make your own note on ACID-BASE TITRATION.