Unit 9- Solution Chemistry

Solution Chemistry: Study of Chemical reactions that occur in solution

9.1 – Solutions and Solubility

Define in your own words and give an example: (p.193)

Solution –

Solvent –

Solute –

Soluble-

Saturated -

Unsaturated –

Solubility -

Assignments: Hebden p.194 #1-4 - Explain: Why is Solution Chemistry so convenient?

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9.2 Conductivity : Chemistry that Kills

+ = _____

OR:

Ye-olde Hair Dryer Ye-olde Bath-tub

+ = ___

Any solution with a sufficient amount of ions will conduct electricity.

So, in order to conduct electricity - solutions must have ______

● ___ ions, ___ conductivity ___ ions, ___ conductivity

The ion is actually a new concept, and the idea of it

revolutionized solution chemistry. In fact,

__________________________, the chemist who

discovered them, won the _______________ in 1903. "in

recognition of the extraordinary services he has rendered

to the advancement of chemistry by his electrolytic theory

of dissociation”.

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Solutions that will conduct

- ______________________ dissolved in water● metal + non-metal

- _______________________● start with H+, end with COOH● end with OH-

* organic acids → conductex: CH3COOH, acetic acid/ vinegar

Solutions that will not conduct

- ________________o non-metal + non–metal

- compounds who’s formulae start with __________ (organic) exception: acetic acid

- Ionic compound → solid

How to decide if a substance is ______________ or _____________

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Assignment: Hebden pg 196 #5bcd, 6-8 (a,c,e,g,i)

9.3 Molecular Polarity

Intermolecular forces - forces _____________ molecules (aka Vander Waals forces)

3 kinds: ___________________________________________________________

1. London Forces

- weak attractive forces that arise because of _____________

- London forces are always present/possible

- the larger _________________, stronger the forces

- due to a temporary ______________

Definiton – Dipole: ___________________________________________________

2. Dipole-Dipole Forces

- due to a ______________________ dipole

- one side of the molecule is _________________ positive and one side is

______________ negative

-for this to happen, the bond must be between two atoms with different

_________________________

Ex. HCl NH3 H2O

3. Hydrogen Bonding

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- special kind of ________________________________ force

- between H and ____, H and _____ or H and

______

- Hydrogen bonds are ________________

than dipole-dipole forces because Hydrogen

has a ____________________________

The information above was only for specific BONDS. Now lets see how this applies to entire MOLECULES (which often have more than one bond)Some definitions:

Polar - a molecule that has a _______________ bond

- __________________(bond dipoles don’t cancel each other out)

- someone will win the tug of war

Non-polar- has a _______________ bond

- ________________(bond dipoles cancel each other out)

- no one will win the tug of war

Examples:

HCl CH3Cl BH3 BeF2

What kinds of forces are involved with the following molecules?

O – O H – Cl - ________ - London - London - __________ - dipole – dipole - ______________

Assignment: Polar Covalent Worksheet and pg. 199-203 #9-10, 14

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O

H H

**** Remember: we are looking at dipoles in COVALENT molecules. Ionic compounds have permanent charges so this doesn’t apply to them****

9.4 Polar and Non Polar Solvents

What is a solvent again?

What does polar mean?

Some examples of Polar and Non-Polar Solvents

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How do we know what dissolves in what? There is a general rule:

“ ________ dissolves __________.”

__________ (ionic) solvents dissolves ____________ (ionic)

________________ solvents dissolves ________________

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But why?

Dissolving process involves _______ different attractions:

1) the attraction of a ___________ molecule to other solvent molecules

2) the attration of a ____________ molecule to _________ particles

3) the attraction of ____________ particles to solute particles

If ____________ is needed to _________ a bond, this must mean energy

must be ______________ when a bond is _________.

If there are ___________ bonds formed between solvent and solute

particles, there is enough energy to allow solute particles to _______ their

bonds. The ________________ of the solvent molecules to each other

allows the broken bonds of the solute to be dispersed and dissolving

occurs.

In-Class Assignment:

Dissolving Proof:

Based on the kind of reasoning above, in partners of 2, have one person explain in written word the process of non-polar solvents dissolving non-polar solutes and why polar solutes do not dissolve. Have the other person explain the polar dissolving process and why non-polar solutes do not

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dissolve in them. Share your work together in pairs, and summarize your findings and proofs.

This must be written on a separate piece of paper, and each person must complete a copy of their own. Your logic is important here as you are proving the statement “Like dissolves like”

1) Solubility of Polar and Ionic Solutes:

2) Solubility of Non Polar Solutes

Assignment: Hebden pg 207 #17-22

9.5 Nature of solution of ions

The process of dissolving is quite complicated. If sugar or salt dissolves in solution, then macroscopically it looks like it is “disappearing”. But as chemists we know better.

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In order for a solution to form, a solute must be able to ___________ in a solvent. This interaction between a solute and solvent is called ____________________.

Ionic solid- solid made of _______ in the form of a ______________ (the orderly arrangement of particles within a crystal)

Na+ =

Cl- =

Molecular solid- solid made from ________________________

C =

H =

From the previous section, the nature of solvation determines the extent to which a solute dissolves.

There are several ways a solute can dissolve into ions:

Dissociation - separating previously existing _______ in ionic solid

NaCl(s) → Na+(aq) + Cl –

(aq)

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OR

Ionization – separating ______________ molecules into ions.

*There are no ions before the solute is able to react with the solvent.

CH3COOH(l) → CH3COO-

(aq) + H+(aq)

Examples:Write an equation to show the dissociation of CaCl2(s) in water.

Write an equation to show the ionization of HCN in water.

9.6 Calculating concentration of ions in solutions

Ending the Solution Chemistry Unit, we will practice some ion concentration calculations based on our knowledge of ion dissociation.

Ex. What is the [F-] in 0.20M AlF3?11

Ex. What is the [ ] of the all the ions when 25.0mL of 0.25M BF3 is mixed with 75.0mL of 0.50M MgF2?

Ex. What is the [OH-] formed when 15.0 g of Fe(OH)3 is dissolved in 0.500 L?

Assigned Work: Hebden pg.210 #28-35

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