Download Ch 7: Reactions

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Stoichiometry wikipedia, lookup

Rate equation wikipedia, lookup

IUPAC nomenclature of inorganic chemistry 2005 wikipedia, lookup

Physical organic chemistry wikipedia, lookup

Biochemistry wikipedia, lookup

Unbinilium wikipedia, lookup

Ununennium wikipedia, lookup

Bioorthogonal chemistry wikipedia, lookup

Isotopic labeling wikipedia, lookup

Process chemistry wikipedia, lookup

Electrolysis of water wikipedia, lookup

Redox wikipedia, lookup

Chemical thermodynamics wikipedia, lookup

Evolution of metal ions in biological systems wikipedia, lookup

Multi-state modeling of biomolecules wikipedia, lookup

Photosynthetic reaction centre wikipedia, lookup

Transition state theory wikipedia, lookup

Marcus theory wikipedia, lookup

Photoredox catalysis wikipedia, lookup

Electrochemistry wikipedia, lookup

Lewis acid catalysis wikipedia, lookup

Chemical equilibrium wikipedia, lookup

Chemical reaction wikipedia, lookup

Hypervalent molecule wikipedia, lookup

Click chemistry wikipedia, lookup

Acid–base reaction wikipedia, lookup

Catalysis wikipedia, lookup

George S. Hammond wikipedia, lookup

Inorganic chemistry wikipedia, lookup

Alkene wikipedia, lookup

Hydroformylation wikipedia, lookup

Strychnine total synthesis wikipedia, lookup

Hofmann–Löffler reaction wikipedia, lookup

Asymmetric induction wikipedia, lookup

Ring-closing metathesis wikipedia, lookup

Cocrystal wikipedia, lookup

Hydrogen-bond catalysis wikipedia, lookup

Woodward–Hoffmann rules wikipedia, lookup

Nucleophilic acyl substitution wikipedia, lookup

Enantioselective synthesis wikipedia, lookup

Organic chemistry wikipedia, lookup

Water splitting wikipedia, lookup

Catalytic reforming wikipedia, lookup

Supramolecular catalysis wikipedia, lookup

Solubility wikipedia, lookup

Transcript
Ch 7: Reactions
• Predicting Whether a Reaction Will Occur
•
Why does a reaction occur? What causes
a reaction to “want” to form products?
• Scientists have recognized several tendencies
in reactants the DRIVE them to form products.
There are several driving forces:
•
•
•
•
Formation of a solid
Formation of water
Formation of a gas
Transfer of electrons
•
When two or more chemicals are brought together, if any of these
things can occur, a chemical change is likely to take place.
• *IF NONE OF THESE FACTORS TAKE PLACE NO REACTION WILL TAKE PLACE
• Our goal is to determine whether a reaction will
occur and what products might form.
All chemical reactions can be placed into one of
six categories:
• 1) Combustion: A combustion reaction is
when oxygen combines with a hydrocarbon (a
combination of C and H) to form water and
carbon dioxide. These reactions are
exothermic, meaning they produce heat. An
example of this kind of reaction is the burning
of napthalene:
• C10H8 + 12 O2 ---> 10 CO2 + 4 H2O
• 2) Synthesis: A synthesis reaction is when two
or more simple compounds combine to form a
more complicated one. These reactions come
in the general form of:
• A + B ---> AB
• One example of a synthesis reaction is the
combination of iron and sulfur to form iron (II)
sulfide:
• 8 Fe + S8 ---> 8 FeS
• 3) Decomposition: A decomposition reaction is
the opposite of a synthesis reaction - a complex
molecule breaks down to make simpler ones.
These reactions come in the general form:
• AB ---> A + B
• One example of a decomposition reaction is the
electrolysis of water to make oxygen and
hydrogen gas:
• 2 H2O ---> 2 H2 + O2
• 4) Single displacement: This is when one element
trades places with another element in a
compound. These reactions come in the general
form of:
• A + BC ---> AC + B
• One example of a single displacement reaction is
when magnesium replaces hydrogen in water to
make magnesium hydroxide and hydrogen gas:
• Mg + 2 H2O ---> Mg(OH)2 + H2
• 5) Double displacement: This is when the anions and
cations of two different molecules switch places,
forming two entirely different compounds. These
reactions are in the general form:
• AB + CD ---> AD + CB
• One example of a double displacement reaction is the
reaction of lead (II) nitrate with potassium iodide to
form lead (II) iodide and potassium nitrate:
•
• Pb(NO3)2 + 2 KI ---> PbI2 + 2 KNO3
• 6) Acid-base: This is a special kind of double
displacement reaction that takes place when an acid
and base react with each other. The H+ ion in the acid
reacts with the OH- ion in the base, causing the
formation of water. Generally, the product of this
reaction is some ionic salt and water: Term “salt” is
used to mean ionic compound
• HA + BOH ---> H2O + BA
• One example of an acid-base reaction is the reaction of
hydrobromic acid (HBr) with sodium hydroxide:
• HBr + NaOH ---> NaBr + H2O
• H2 + F2 = 2HF
• H2 +0
+
F2
+0
=
H +1 F
-1
• hydrogen lost an electron to become positively charged ………..OIL
• Fluorine gained an electron to become negatively charged……RIG
• Substance oxidized: Hydrogen
Oxidation Reaction: H2 → 2H+ + 2eSubstance reduced: Fluorine
Reduction Reaction: F2 + 2e- → 2F• ****A lot of reactions are redox and another
type of reaction from the above list.
• 7*) Special Reaction Type: Redox: or oxidation-reduction
reactions, primarily involve the transfer of electrons
between two chemical species. The compound that loses
an electron is said to be oxidized (OIL = oxidization is loss),
the one that gains an electron is said to be reduced (RIG =
reduced is gained).
• *If the element stands alone its net charge is ZERO.
• *If the element is contained in a compound then you must
look at their individual oxidation numbers (periodic table)
• *If it is a transition metal you must split the compound
apart and figure out the charge on the transition metal
based off of its partner (like you did in chapter 5 when
naming)
• ***YOU MUST FIRST FIGURE OUT THE
REACTION TYPE 1-6 AND THEN DECIDE IF IT IS
ALSO A REDOX REACTION
• Questions to ask yourself if you cannot figure out the type of
reaction:
• Follow this series of questions. When you can answer "yes" to a
question, then stop!
• 1) Does your reaction have oxygen as one of it's reactants and
carbon dioxide and water as products? If yes, then it's a combustion
reaction
• 2) Does your reaction have two (or more) chemicals combining to
form one chemical? If yes, then it's a synthesis reaction
• 3) Does your reaction have one large molecule falling apart to make
several small ones? If yes, then it's a decomposition reaction
• 4) Does your reaction have any molecules that contain only one
element? If yes, then it's a single displacement reaction
• 5) Does your reaction have water as one of the products? If yes,
then it's an acid-base reaction
• 6) If you haven't answered "yes" to any of the questions above,
then you've got a double displacement reaction
•
•
•
•
•
•
•
•
Examples to figure out:
1) NaOH + KNO3 --> NaNO3 + KOH
2) CH4 + 2 O2 --> CO2 + 2 H2O
3) 2 Fe + 6 NaBr --> 2 FeBr3 + 6 Na
4) CaSO4 + Mg(OH)2 --> Ca(OH)2 + MgSO4
5) NH4OH + HBr --> H2O + NH4Br
6) Pb + O2 --> PbO2
7) Na2CO3 --> Na2O + CO2
• Answers:
• 1) double displacement
2) combustion
3) single displacement
4) double displacement
5) acid-base
6) synthesis
7) decomposition
• Solubility Tables
• A Solubility Table summarizes the solubility
behavior of a large group of ionic substances.
How to interpret a Solubility Table?
Example 1:
Example 2:
• We can use the Solubility Table to determine whether
an ionic compound exist as ions in aqueous solution
(soluble) or as a solid (insoluble). Once we know the
compound we use the Solubility Table to determine its
solubility.
• For example, consider the following compounds; NaCl,
BaSO4, NaC2H3O2, and CaS. Determine the solubility in
water for these ionic substances.
• NaCl (all chlorides are soluble except...) SOLUBLE =
aqueous
• BaSO4 (all sulfates are soluble except...) INSOLUBLE =
solid
• NaC2H3O2 (all sodium compounds are soluble) SOLUBLE
= aqueous
• CaS (all sulfides are insoluble...) INSOLUBLE = solid
• We'll also use the information in a Solubility
Table to help identify the phase of ionic
substance in a chemical equation. The
chemical reaction types where the Solubility
Table is important are;
• Double Replacement reactions
• Neutralization reactions
• Single Replacement reactions
• Example 1: double displacement reaction
problem;
• Write the formula and identify the phase for the
product(s) and balance the following reaction.
• Na2SO4(aq) + CaCl2(aq) --->
• Since this is a double replacement reaction we
can write the formulas of the products by
exchanging the cations and anions.
• Na2SO4(aq) + CaCl2(aq) ---> CaSO4(?) + 2NaCl(?)
• Now we'll use the Solubility Table to predict the
phases of the products. According to the table
CaSO4 is INSOLUBLE and NaCl is SOLUBLE.
• Na2SO4(aq) + CaCl2(aq) ---> CaSO4(s) + 2NaCl(aq)
• Example.2: double displacement reaction problem
• Write the formula and identify the phase for the
product(s) and balance the following reaction.
• AgNO3(aq) + Na2CO3(aq) --->
• Since this is a double replacement reaction we can
write the formulas of the products by exchanging the
cations and anions.
• 2AgNO3(aq) + Na2CO3(aq) --->Ag2CO3(?) + 2NaNO3(?)
• Now we'll use the Solubility Table to predict the phases
of the products. According to the table Ag2CO3 is
INSOLUBLE and NaNO3 is SOLUBLE.
• 2AgNO3(aq) + Na2CO3(aq) ---> Ag2CO3(s) + 2NaNO3(aq)
• Example 3:
• KNO3(aq) + BaCl2 (aq) ) --->
• Example 4:
• Na2SO 4(aq) + Pb(NO3)2(aq) ) --->
• Example 5:
• KOH (aq) + Fe(NO3) 3(aq)
)
--->