chemical reactions Flashcards
Collision Theory
For a chemical reaction to happen,
particles (atoms, molecules, or ions) must
collide, and the collisions must result in
rearrangement of the interacting atoms.
How does Temperature affect reaction rate
Raising the temperature increases the speed at
which the molecules move.
When molecules move faster, more collisions
occur, thus making the reaction proceed
faster. The opposite is true for decreasing
the temp.
How does concentration affect reaction rate
When the concentration is increased, the
number of molecules are increased.
When there are more molecules, more
collisions occur, thus making the
reaction proceed faster.
The opposite is
true for decreasing the concentration.
How does particle size affect reaction rate
When the size of the particles are smaller the
surface area is increased. This provides
access to a greater number of molecules and
increases the speed of the reaction.
The
opposite is true for using larger particle sizes.
How do Catalysts affect reaction rate
A catalyst is never used up in a reaction, but it’s
presence can speed up a reaction by
lowering the energy it takes for collisions to
occur.
What are the two types of energy in chemical reactions
Kinetic Energy (KE) – energy of motion
*Potential Energy (PE) - energy stored due to
position.
What’s a exothermic reaction
Exothermic Reaction - energy (or heat)
is released, reaction feels warm
energy written as a product
What’s a endothermic reaction
Endothermic Reaction- energy (or heat)
is absorbed, reaction feels cool
energy is written as a reactant
Law of Conservation of Mass
neither created nor destroyed. The form of
matter may change, but the TOTAL amount
of mass stays constant.
Law of Conservation of Energy
energy is
neither created nor destroyed. The form or
kind of energy may change, but the TOTAL
amount of energy stays constant.
What is Synthesis?
A + B -> AB
Synthesis reactions occur when two or
more reactants combine to form one
new compound.
What is Decomposition?
AB -> A + B
Occurs when one reactant breaks down
into two or more products.
What is Single Replacement?
A + BC –> B + AC
One element replaces another element
(of the same charge) in a compound.
energy of new element has to be higher according to Activity Series
What is Double Replacement?
AB + CD –> AD + CB
Occurs when two elements in two
compounds switch places.
Make sure to match positive and negative
ions together!
happens b/c one soluble and one insoluble product
happens b/c a salt and a water
What is Combustion?
When a Hydrocarbon (a compound
containing hydrogen and carbon) burns in
Oxygen. Carbon dioxide and Water are
the only products.
