Transcript Unit 3 - Salina USD 305

Unit 7
Chemical
Reactions –
Ch. 11
Today…
Before Class:
◦ New Seats
 Our Plan:
◦ Introduce yourself to your new lab partner
◦ New Calendar
◦ Evidence of Chemical Change Lab
◦ Wrap Up – How do we know a reaction took
place?
 Homework (Write in Planner):
◦ Finish all lab questions – due next class

Today…



Before Class:
◦ Pick up Calendar, Notes, & Worksheet Packet
Our Plan:
◦ Review & Ionic Insanity Game
◦ Naming Compounds Worksheet
◦ Daily Challenge - Definitions
◦ Notes – Balancing Equations
◦ Worksheet #1
◦ Wrap Up – chembalancer online
Homework (Write in Planner):
◦ Review Worksheet – due next class
Remember Naming?
Compound
Type
Made
of
Rules Rules for
Writing
for
Naming Formulas
Examples
Ca(NO3)2
Ionic
Ammonium phosphate
C6H7O2
Covalent
Dinitrogen pentahydride
Ionic Insanity Rules






Each player selects a game piece.
Play begins with the student with the longest name.
The student rolls a cation dice and an anion dice.
Based on what the dice land on, the student will say the
formula and the name for the compound.
It is up to the other members of the group to
determine if the name and formula are correct. If the
formula is right, the student gets to move 3 spaces on
the board. If the name is correct they get to move 2
spaces. Both correct answers result in a player moving
5 spaces on the game board.
Play continues clockwise. The game ends when a
student gets to the end of the game board. That
student is the winner.
Let’s try a few from the WS…
Daily Challenge
 As
a table, come up with a
definition for each of the
following terms that we’ve
already covered:
◦ Subscript
◦ Law of Conservation of Mass
◦ Reactant
◦ Product
Chemical Reactions with Bill Nye

http://www.youtube.com/watch?v=66kuhJ
kQCVM
Indication of a Chemical
Reaction
1.
2.
3.
4.
Evolution of heat &
light
Production of a gas
Formation of a
precipitate (solid)
Color Change
Word Equation
An
equation in which
the reactants &
products in a chemical
reaction are
represented.
QUALITATIVE ONLY
Example
Methane
plus
oxygen forms
carbon dioxide plus
water
Reactants & Products
Label the Reactants and
Products in the Example
given:
Methane plus oxygen
forms carbon dioxide
plus water
Chemical Equation
Represents
with symbols &
formulas the reactants & the
products in a chemical
reaction
QUALITATIVE &
QUANTITATIVE
2H2 + O2 --> 2H2O
Reactants & Products
Label
the Reactants and
Products in the Example
given:
2H2 + O2 --> 2H2O
Coefficient
Small
whole
number that
appears in front of a
formula in a
chemical equation
Coefficient
Tells
how many
moles there are
4KClO3 = 4 moles
of potassium
chlorate
Counting Atoms
4KClO3
◦4 K
◦4 Cl
◦12 O
=
Counting Atoms
3Mg(NO3)2
=
◦3 Mg
3 Mg
◦6 N OR 6 NO
3
◦18 O
Think about it…
What things do you think
can be done to increase the
rate of a reaction?
Rate of Reaction

Reaction rate can be affected by:
◦
◦
◦
◦
◦

Temperature
Surface Area
Concentration
Pressure
Addition of a Catalyst
There is an entire area of chemistry that
focuses on rates of reactions. It is called
KINETICS.
Catalyst
A
substance that speeds
up a reaction, but is not
used up in the reaction
It is neither a reactant,
nor a product
Solubility
Soluble
– a substance that
can be dissolved
(AQUEOUS)
Insoluble – a substance that
does not dissolve (SOLID)
Symbols
Yields
Reversible
◦Products reform
original reactants
Solid (s)
Symbols
(l )
Aqueous (aq)
◦Dissolved in
water
Liquid
Symbols
Gas (g)
Reactants heated
heat
Catalyst
Pt
Law of Conversation of
Mass
In
a reaction,
mass is neither
created, nor
destroyed
What Does This Mean?
 The
amount of products
are equal to the amount of
reactants
 Need the same number of
atoms of an element on
each side of an equationBALANCE!
To Balance an Equation
1.
Write out the
equation using the
correct symbols &
formulas
To Balance an Equation
2.
◦
Count the number of
atoms of each element
on each side of the
arrow
Count a polyatomic ion
as a single unit if it
appears unchanged on
both sides of the
equation
To Balance an Equation
3.
◦
Add coefficients
ONLY to balance
the number of
atoms on each
side
Never change the
subscripts!
To Balance an Equation
Recheck your atoms
on each side
5. Make sure
coefficients are in
the lowest possible
ratio
4.
Rule of Thumb!
Always
balance
hydrogen & oxygen
last!
If there is an odd
number, double it!
Example:
H2 + O2
H2O
Practice Problem 1
Na + Cl2
NaCl
Practice Problem 2
K + H2O
KOH + H2
Practice Problem 3
Al2(SO4)3 + Ca(OH)2
Al(OH)3+ CaSO4
Try it on your own!
Rb
+
Al +
Al4C3+
S8
ZnCl2
H2O
Rb2S
Zn +
CH4 +
AlCl3
Al(OH)3
The Answers
16Rb + S8 --> 8Rb2S
 2Al + 3ZnCl2 --> 3Zn + 2AlCl3
 Al4C3 + 12H2O --> 3CH4 + 4Al(OH)3

STOP!
Complete
Worksheet
# 1 by next
class
Wrap Up
1.
2.
3.
Get your Chromebook
Go to
http://funbasedlearning.com/chemistry/ch
emBalancer/
Complete the equations
Today…
Turn in:
◦ Worksheet #1
 Our Plan:
◦ Balancing Race
◦ Balancing Quiz
◦ Notes – How Chemistry is Like Love
◦ List-Group-Label Reactions
◦ Begin Worksheet #2
◦ Wrap Up – Reaction Sort
 Homework (Write in Planner):
◦ Worksheet #2 (Optional)

Types of chemical
reactions
How
chemistry is like
LOVE!
Why do we classify types of
reactions?
 There
are thousands of reactions
around us, so we need a way to classify
them.
 There are 5 major ways to classify
reactions.
 If you can classify a reaction into one of
the categories, you know a lot about it
and you can predict products.
 Like the Linnaeus system!
Combination (Synthesis) Reactions
aka “Dating”
Definition: 2 or
more
substances react to
form a single new
substance
Synthesis Reactions
General
equation
A + X --> AX
Examples
◦2Mg + O2 --> 2MgO
◦2Na + Cl2 --> 2NaCl
Synthesis Reaction
2Na + Cl2
2NaCl
Decomposition Reactions
aka “The
Breakup”
Definition- a single
compound undergoes a
reaction that produces
2 or more simpler
substances
Decomposition Reactions
General
equation
AX --> A + X
Examples
◦2HgO --> 2Hg + O2
◦2KClO3 --> 2KCl + 3O2
Decomposition Reaction
2NI3(s) → N2(g) + 3I2(g)
Single-Replacement Reactions
aka “Cheating”
Definition
– one
element replaces a
similar element in a
compound
Single-Replacement Reactions
 General
Equation:
A + BX --> AX + B or
Y + BX --> BY + X
 Examples
◦ Mg + 2HCl --> H2 + MgCl2
◦ Cl2 + 2KBr --> 2KCl + Br2
Single Replacement Reactions
2Mg + CO2 --> 2MgO + C
Single Replacement
 Single
replacement reactions only
occur when a more reactive element is
available to take the place of a less
reactive element in solution.
 Remember reactivity on the Periodic
Table?
◦ Francium is the most reactive metal
◦ Fluorine is the most reactive nonmetal
Example
 Mg
+ Zn(NO3)2 → Mg(NO3)2 + Zn
◦ Because Mg is more reactive than Zn, it
can take its place.
 Zn
+ Mg(NO3)2 → No Reaction
◦ Because Zn is less reactive than Mg, no
reaction will take place.
Try it Out…
Will
a reaction occur?
◦Ag + Ca(NO3)2 →
◦F2 + CaCl2 →
◦K + AgNO3 →
Double-Replacement Reaction
aka “Swapping”
Definition – positive
ions of 2 compounds
exchange places
◦Usually happens in an
aqueous solution and
often produce a
precipitate or a gas
Double-Replacement Reactions
General
Equation
AX + BY --> AY + BX
Examples
◦ 2KI+Pb(NO3)2-->PbI2+2KNO3
◦ HCl+NaOH-->NaCl+HOH
Double-Replacement Reaction
2NaI + HgCl2 --> 2NaCl + HgI2 (s)
Combustion Reaction
 aka “O2
Cute!”
 Definition – a
substance combines
with oxygen (O2),
releasing a large
amount of energy in
the form of light &
heat
Combustion Reaction
 General
equation – O2 is
always a reactant and CO2
and H2O are usually
products
 Examples
◦ C3H8 + 5O2 -->3CO2 + 4H2O
◦2H2 + O2 --> 2H2O
Whoosh Bottle Demonstration

http://www.youtube.com/watch?v=AS8TD
pFP0OQ
STOP!
Complete
the List-GroupLabel activity in your
notebooklet.
Compare your answers
with your shoulder-partner.
Tip!
Always
write water
+1
-1
as H OH
Decomposition Rxns
 They
are difficult to predict
because different compounds
break apart differently.
 Match up the type of
decomposition reaction with
the ones that follow and
predict the products.
Decomposition Rxns
 Decomposition
of Binary
Compounds:
 Breaks apart into its 2
components
◦ 2H2O --> 2H2 + O2
◦ 2HgO --> 2Hg + O2
Decomposition Rxns
Decomposition
of Metal
Carbonates
Breaks apart to form a
metal oxide and carbon
dioxide gas
◦ CaCO3 --> CaO + CO2
Decomposition Rxns
Decomposition
of Metal
Hydroxides
Breaks apart to form a
metal oxide and water
◦ Ca(OH)2 --> CaO + H2O
Decomposition Rxns
Decomposition
of Metal
Chlorates
Breaks apart to form a
metal chloride and oxygen
gas
◦ 2KClO3 --> 2KCl + 3O2
Decomposition Rxns
 Decomposition
of Acids
 Breaks apart to form a
nonmetal oxide and water
◦ H2CO3 --> CO2 + H2O
◦ H2SO4 --> SO3 + H2O
Example 1

Hydrogen + chlorine -->
Example 2

iron (III) sulfate + hydrochloric acid -->
Example 3

potassium iodide + bromine -->
Example 4

magnesium oxide -->
Wrap Up
Reaction
Sort
Today…
Turn in:
◦ Get out WS #2, notebooklet, and your PT
 Our Plan:
◦ Find Someone Who
◦ WS Problems
◦ Worksheet #2
◦ Wrap Up – Reaction Sort
 Homework (Write in Planner):
◦ WS #2 Due Thursday/Friday

Types of Reactions Review

Combination (Synthesis) –

Decomposition –

Single Replacement –

Double Replacement –

Combustion -
Find Someone Who
 Get
a reaction card.
Complete the Find Someone
Who Activity in your
notebooklet on p. 11 by
finding students who match up
with the different reaction
types.
#1 Worksheet

Sodium iodide + chlorine -->
#3 Worksheet

Rubidium + bromine -->
#6 on Worksheet

Magnesium chlorate -->
# 8 on Worksheet

Carbon tetrahydride + oxygen -->
#21 on Worksheet

potassium + water -->
#22 on Worksheet

silver carbonate -->
#23 on Worksheet

Octane (C8H18) + O2 -->
#25 on Worksheet

Calcium sulfate + phosphoric acid -->
#32 Worksheet

Aluminum + sulfuric acid -->
Stop!
Work
on WS#2
Wrap Up
Reaction
Sort
Today…
Turn in:
◦ Get out WS#2
 Our Plan:
◦ Find Your Match & then Balance
◦ Work on WS#2
◦ Types of Reactions Lab
◦ Wrap Up - Password
 Homework (Write in Planner):

◦ WS#2 Due Next Class
Today…
Turn in:
◦ Worksheet #2
◦ Try It Out (p. 13 of notes)
 Our Plan:
◦ Daily Challenge (p. 13)
◦ Quiz
◦ Lab
 Homework (Write in Planner):
◦ Nothing

Try It Out Answers…
Daily Challenge
Label each reaction below as to
its type (p. 13):
1. 2NaI + HgCl2 --> 2NaCl + HgI2
2. 2NI3(s) → N2(g) + 3I2(g)
3. 2Na + Cl2 --> 2NaCl

4.
Write the balanced chemical equation
for the reaction between iron (III)
oxide and aluminum.
Daily Challenge
 The
Equation:
 Type
of Reaction:
Thermite Reaction Video
http://www.chem.leeds.ac.uk/delights/animations/thermite.html
Quiz – identify the type of reaction
and write a balanced equation.
1a. Sodium iodide + chlorine -->
1b. Strontium bromide + ammonium sulfide -->
2a. Strontium + water -->
2b. Sulfuric acid + sodium chloride -->
3a. Aluminum + potassium sulfate -->
3b. Hydrogen + fluorine -->
4a. Cobalt (II) sulfate + sodium -->
4b. Aluminum + iodine -->
Today…



Turn in:
◦ Worksheet
Our Plan:
◦ Review (?)
◦ Notes - Net Ionic Equations
◦ Worksheet #3
◦ Finish Lab – DUE TODAY
◦ Wrap Up – Quiz, Quiz, Trade
Homework (Write in Planner):
◦ WS#3 – Due Next Class
Net Ionic Equations
Dissociation
– The
separation of ions that
occurs when an ionic
compound dissolves

NaCl (s) --> Na+ (aq) + Cl- (aq)
Dissociation
Net Ionic Equations
Precipitation
Reactions – a
double replacement
reaction in which a
solid (precipitate) is
produced
Net Ionic Equations
A
precipitate forms because it is
insoluble in the solution.
 To identify whether a compound
will be a solid or aqueous, use a
solubility table (R54)
A little humor…
Sample Solubility Table
Net Ionic Equations
Example:
◦BaI in water
◦Ca(OH)2 in water
◦CuS in water
◦AlCl3 in water
Net Ionic Equations
 Spectator
Ion – Ions that
do not take part in a
chemical reaction and are
found in solution (aqueous)
both before and after the
reaction
Net Ionic Equations
 Net
Ionic Equation – an
equation that includes only those
compounds or ions that undergo a
chemical change in a reaction in an
aqueous solution (those that form
precipitates)
To Write Net Ionic Equations
1.
2.
3.
Rewrite the equation to show
dissociation
Cancel out the spectator ions
Rewrite the equation – this is
the net ionic equation
Example
 Write
the net ionic equation for:
Zn(NO3)2 (aq) + (NH4)2S (aq) -->ZnS (s) + 2NH4NO3(aq)
Another Example

Na2CO3 (aq) + CaCl2 (aq) --> 2NaCl (aq) + CaCO3 (s)
Try It Out!

Ag2SO4 (aq) + 2KCl (aq) --> 2AgCl (s) + K2SO4 (aq)
STOP!
Complete
the Net Ionic
Worksheet (#3)
Finish the Types of
Reactions Lab
Wrap Up
Quiz, Quiz Trade
Today…
Turn in:
◦ Worksheet #3
 Our Plan:
◦ Net Ionic Equations Review
◦ Around the Room Review
◦ Unit 7 Lab Test
◦ Wrap Up –Slap Jack Vocab Review

 Homework
(Write in Planner):
◦ Lab Test due Monday
Net Ionic Equation Review

Write the complete and net ionic
equation for:
◦ Ag2SO4 (aq) + 2KCl (aq) --> 2AgCl (s) + K2SO4 (aq)
Lab Test Set Up:
Today…
Turn in:
◦ Unit 7 Lab Test
 Our Plan:
◦ Missing Work
◦ Test Review
◦ Clicker Review
 Homework (Write in Planner):
◦ Test Review due next class
◦ Unit 7 Test Next Class

Today…
Turn in:
◦ Get Out Test Review to check
 Our Plan:
◦ Station Review
◦ Questions on Test Review
◦ Test
◦ Forensic Farming Reading
 Homework (Write in Planner):
◦ Reading due next time
