Chapter 6 Student Guided Notes 6.1 Types of Chemical Reactions

Name:_____________________
Date:__________________
Chapter 6 Student Guided Notes
6.1 Types of Chemical Reactions
Synthesis - Synthesis reactions are also known as _______________________.
Definition: A synthesis reaction is when ____________________________ (usually
elements) join to form a _____________________.
____________________________ where A and B represent
____________________ The elements may form _________________________, like
these:
o Sodium metal and chlorine gas combine to form sodium chloride.
2Na + Cl2 −−> 2NaCl
o Magnesium metal reacts with oxygen gas to form magnesium oxide.
2Mg + O2 −−> 2MgO
Or the elements may form ______________________________, like this:
o Nitrogen gas and oxygen gas join to form dinitrogen monoxide.
2N2 + O2 −−> 2N2O
Decomposition - Decomposition reactions are
the
_________________________________________.
Definition: A decomposition reaction is when
_______________________________ into two or more
products (often elements).
• ______________________________ where A
and B represent elements
Ionic compounds may decompose to produce
elements, like this:
• Table salt, sodium chloride, can be broken down
into sodium metal and chlorine gas by melting
salt at 800ºC and running electricity through it.
2NaCl −−>2Na + Cl2
Covalent compounds may decompose into elements, like this:
• By running electricity through water, the water molecules decompose into
hydrogen and oxygen gases.
2H2O −−> 2H2 + O2
Name:_____________________
Date:__________________
Single Replacement - Single replacement reactions replace ______________
____________________ with a ________________________ added as a reactant.
Definition: A single replacement reaction is when a compound and an element react,
and the element switches places with part of the original compound.
o _____________________________ where A is a metal, or
o _____________________________ where A is a non-metal
When A is a metal:
• Aluminum foil in a solution of copper II chloride produces solid copper and
aluminum chloride.
Al + CuCl2 −−> Cu + AlCl3
When A is a non-metal:
• When fluorine is bubbled through a sodium iodide solution, iodine and sodium
fluoride are produced.
Fl2 + NaI −−> I2 + NaF
Double Replacement - Double replacement reactions
_____________________________________________ reacting
together to form two new compounds.

Definition: Double Replacement is when ____________________
_____________, with elements switching places between the
original compounds.
• Two solutions react to form a precipitate (ppt, solid) and
another solution
Ionic soln + ionic soln −−> ionic soln + ionic soln/ppt
________________________________
•
When potassium chromate and silver nitrate react, they form a red precipitate,
silver chromate, in a solution of potassium nitrate.
K2CrO4 + AgNO3 −−> Ag2CrO4 + KNO3
Neutralization - Neutralization reactions occur when an ___________________
Name:_____________________
Date:__________________
________________________________________.
Definition: Neutralization is when an_____________ (most compounds starting with H)
and a ______________ (most compounds ending in OH, or beginning with NH4) react.
o ________________________________________
o HX + MOH −−> MX + H2O where X and M are elements
•
•
Sulphuric acid is used to neutralize calcium hydroxide:
H2SO4 + Ca(OH) 2 −−> CaSO4 + 2H2O
Phosphoric acid helps to neutralize the compounds that cause rust, such as iron
(II) hydroxide.
H3PO4 + 3Fe(OH)2 −−> Fe3(PO4)2 + 6H2O
Combustion - Combustion reactions occur when a _______________________
___________________________ with
________________to release______________ and
produce an ____________
Also sometimes referred to as hydrocarbon combustion
Definition: A combustion reaction is when a hydrocarbon
reacts with Oxygen to produce Water and Carbon Dioxide
• __________________________________ where X
and Y represent integers
o Natural gas (methane) is burned in furnaces to
heat homes.
CH4 + O2 −−> CO2 + 2H2O
o An acetylene torch is used to weld metals
together
2C2H2 + 5O2 −−> 4CO2 + 2H2O
o Carbohydrates like glucose combine with oxygen in our body to release
energy.
C6H12O6 + 6O2 −−> 6CO2 + 6H2O
Summary of Reactions
Name:_____________________
Date:__________________
6.2 Rates of Chemical Reactions
General Information
Often, controlling the rate of a chemical reaction is as important as having the
reaction occur in the first place.
• Many factors can determine the rate a chemical reaction occurs.
To make a reaction __________________________
• _______________ the ___________________ where the reaction occurs
• _______________ the ___________________ of reactants
• I______________ the amount of _________________________ that reacts
• ________ a ____________, or ____________ an _____________
To make a reaction happen ______________:
• ____________ the _______________ where the reaction occurs
• ____________ the _______________ of reactants
• ____________ the amount of _____________________ that reacts
• ______________ a ____________ (if present), or ________ an_____________
Temperature
Temperature is a measure of the average energy of molecules.
• The more energy molecules have, the
higher the temperature.
• When molecules ____________________
_______________, they ______________
_______, bump into other molecules more,
and therefore ___________________.
Name:_____________________
Date:__________________
The rate of reaction changes with the temperature.
• ________________________ = ________________________, and vice versa.
• Sometimes we want slower reactions (we use a fridge to prevent spoilage).
• Sometimes we want faster reactions (we cook food to speed up the production of
new molecules).
Concentration
Concentration refers to _________________________________________________
_________________________________.
• How much solute (what’s dissolved) is there in a certain amount of solvent (what
the substance is dissolved in.
• Concentration is measured in mass per unit volume (g/L).
Usually, the _____________ the concentration of reactants, the _____________
the reaction occurs.
• Since there are more molecules per unit volume in high concentrations, there are
more opportunities for molecules to collide and react.
• A splint of wood glows brighter in highly concentrated oxygen than in normal air,
with a lower concentration of oxygen.
Surface Area
Chemical reactions occur _______________________________________________
____________________________.
• The more atoms and molecules there are to collide, the higher the reaction rate.
___________________surface area ___________________ the rate of reaction.
• Since there are _______________________________________________,
more reaction takes place.
• Surface area can be increased by ________________________________.
• A powdered substance has far more surface area than one, large chunk.
• The increase in surface area must also be exposed for reaction; a powder only
reacts more quickly if it is spread into the air instead of lying on a pan.
Catalysts
Sometimes increasing the temperature or concentration is not a desirable method
to increase reaction rate.
• Changing these two variables may be impractical or dangerous
.
A catalyst is a chemical that allows a reaction to occur more quickly __________
________________________________________.
• The catalyst _______________ the reaction rate, but does not get used up as a
reactant.
Name:_____________________
•
Date:__________________
Catalysts ________________________________________________ to break
the bonds in the reactants.
________________ are an example of _______________________________
• Saliva has enzymes that help speed the breakdown of starches when they enter
the mouth.
A catalytic converter is a device installed in all cars to decrease pollution.
• Car exhaust passes through the catalytic converter before leaving the car.
• Catalysts found in the honeycomb-shaped filters in the converter help to change
many of the pollutants.
o
Poisonous carbon monoxide is changed into CO2
o Hydrocarbons are converted into CO2 and H2O
o Nitrogen oxides are changed into N2 and O2
 2N2O3 −−> 2N2 + 3O2