Transcript + + Chemical Reactions

Chemical Changes (Reactions)
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Reactants
Products
Synthesis
Single Replacement
Double Replacement
Decomposition
Chemical Reactions
• Indicators
– Fizzing (gas produced)
– Color change
– Gets cloudy/precipitant (solid produced)
– Heat released or absorbed
– Light emitted
– Odor changes
Chemical Reactions
http://ed.ted.com/lessons/if-molecules-were-people-george-zaidan-and-charles-morton
• Reactants  Products
• H2O2  H2O + O2
–What are the reactants? What are the
products?
Chemical Reactions
There are 4 kinds of Chemical
Reactions that occur:
Synthesis
Decomposition
Single
Replacement
Double
Replacement
Chemical Reactions
• Synthesis
–Two or more reactants are
combined to form one
product.
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Chemical Reactions
• Decomposition
–One reactant breaks down
into two or more products.
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Chemical Reactions
• Single Replacement
–An element and a compound combine.
–One element from the reactants
replaces another in the products.
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Chemical Reactions
• Double replacement
–Two compounds combine.
–Two elements in the reactants switch
places in the products.
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Chemical Reactions-Practice
Identifying
• Example #1
• H2 + O2  H2O
Which is it?
• Synthesis
• Decomposition
• Single Replacement
• Double
Replacement
Chemical Reactions
• Example #2
• Li3P  Li + P
Which is it?
• Synthesis
• Decomposition
• Single
Replacement
• Double
Replacement
Chemical Reactions
• Example #3
Which is it?
• Na + MgCl2  Mg + NaCl• Synthesis
• Decomposition
• Single
Replacement
• Double
Replacement
Chemical Reactions
• Example #4
Which is it?
• SiCl4 + O2  SiO + Cl2
• Synthesis
• Decomposition
• Single Replacement
• Double
Replacement
Chemical Reactions
• Example #5
• C5O3  C + O2
Which is it?
• Synthesis
• Decomposition
• Single Replacement
• Double
Replacement
Chemical Reactions
• Example #6
• Rb2O + AlF3  RbF + Al2O3
Which is it?
•
Synthesis
•
Decomposition
•
Single
Replacement
•
Double
Replacement
Chemical Reactions
• Law of conservation of Matter
–Atoms are not created or destroyed
–The number of atoms at the START
of a reaction, there must be the same
number of atoms AFTER the
reaction.
–Equations must be balanced!
Chemical Reactions
• Balancing Chemical Equations STEPS:
–Count the number of atoms for each
element in the reactants and in the
products.
–Compare the numbers to see if each
element is balanced (equal) with itself.
–Use WHOLE NUMBER coefficients to
“fix” unbalanced elements.
• Do not change the subscripts!
Chemical Reactions
• Balancing Chemical Equations STEPS:
–Whole number coeficients go in front of the
compound or element in the equation and
multiply every atom after it.
–Ex: NaCl3 has 1 Na atom and 3 Cl atoms
but if I needed to have 2 Na atoms in my
reactants or products, I would put a coefficient
of 2 in front of the compound NaCl3…..
2NaCl3 and now I would have 2 Na atoms, but
also 6Cl atoms
Chemical Reactions
• Example #1
• H2 + O2  H2O
• H-2
H-2
• O-2
O-1
• 2H2 + O2  2H2O BALANCED
• H-4
H-4
• O-2
O-2
Chemical Reactions
• Example #2
• Li3P  Li + P
• Li-3
Li-1
• P-1
P-1
• Li3P  3Li + P
BALANCED
• Li-3
Li-3
• P-1
P-1
Chemical Reactions
• Example #3
• C5O3  C + O2
• 2C5O3  10C + 3O2
BALANCED
Chemical Reactions
• Example #4
• Rb2O + AlF3  RbF + Al2O3
Chemical Reactions
• Example #5
SnO2 + H2 → Sn + H2O
Chemical Reactions
• Example #6
• Mg(ClO3)2 + Na  NaClO3 + Mg
Chemical Reactions
• Example #7
• Al2(SO4)3 + RbF  AlF3 + Rb2SO4
Chemical Reactions
• Identify and Balance
•
Al + F2  AlF3
Chemical Reactions
• Identify and Balance
•
Ca(MnO4)2 +
FeCl4 
CaCl2 +
Fe(MnO4)4
Chemical Reactions
• Identify and Balance
•
Si3O  Si8 + O2
Chemical Reactions
• Identify and balance
•
Cs2O + N2  Cs3N + O2
Warm Up
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Classify the following chemical reactions as
decomposition, single replacement, double
replacement or synthesis:
For the first equation, what are the reactants
and what are the products?
Write the chemical formula for Barium
Nitride
Acids and Bases
Draw a Line Like this in the
middle of your paper
c
0
0
\
7
14
You will cut out the pictures you get on the paper and arrange them
along the pH scale you have drawn. Do your best to guess where things
might go…DO NOT glue them down until you check with me firstu
Acids properties
1.
2.
3.
Conduct electricity
(electrolytes)
Produce H+ ions
Sour taste
4. Corrosive
5.
pH values 0-6.9
Acids
Acids
pH range = 0-6.9
• Examples: Citric Acids,
Gastric Acid, Battery Acid,
Sodas, tomatoes, etc.
• Examples of Formulas: HCl,
H2SO4, H3PO4, HNO3, etc
SPOILED
MILK
Bases
properties
1.
Conduct electricity
(electrolytes)
2.
OH- ions
3.
Bitter taste
4. Corrosive
5.
Have a slippery feeling (like
soap)
6.
pH values 7.1-14
Bases
Bases pH range 7.1 to 14
• Examples: Soaps, Cleaning supplies,
Hair Relaxers, etc.
• Examples of Formulas: NaOH,
KOH, Mg(OH)2, Al3(OH), NH3,
NH OH
Acids & Bases-pH Scale
Acids and Bases-Compare & Contrast
Acids and Bases--Identify
1.
2.
3.
4.
5.
6.
7.
8.
pH =2
HF
pH= 7
RbOH
Ca(OH)2
pH= 9
Sour taste
Slippery feel
9. Electrolyte
10.pH = 13
11.pH = 4
12.H2SO4
13.HBr
14.FrOH
15.Corrosive
16.Bitter taste
Acids & Bases
• Neutralization Reactions
Only an Acid can neutralize a base
Only a Base can neutralize an acid
• H+ comes off of the Acid and OHcomes off of the Base (OH and H
make water!)
• Acid + Base  Water + Salt
Ex: HCl + KOH  H2O + KCl
Acid/Base Neutralization
• HBr + LiOH  _________ + _________
• FrOH + HCl  _________ + _________
• H2S + Mg(OH)2  ________ + _______
• ______ + HF  H20 + KF
• ______ + CsOH  H20 + CsI