Transcript Warm UP - Appoquinimink High School

Warm UP
1. Name one type of chemical bond and tell me how
it bonds.
2. Drawl an Lewis dot diagram of an atom of Oxygen
which has an atomic number of 8 (hint first figure
out how many valence electrons it has)
3. Which of the three bonds is the weakest?
4. Which chemical bond is formed when two
atoms share electrons?
• Chemical Reaction – a process
that changes one set of chemicals
into another.
– Involves the breaking and forming of
new bonds. Quantity remains the
same.
• 1+1=2
1+1 2
• If this represented a chemical
reaction, then 1=reactants and 2 =
product
• The reactants “react” to form the
product.
Synthesis/Anabolic Reaction: when two or more atoms
bond to form a more complex structure.
Example: fixing worn or damaged
tissues requires a build up of smaller
molecules coming together to make a
larger molecule.
A+B
AB
Decomposition/catabolic reaction: When a bond
holding atoms together breaks and produces a simpler
molecule.
Example: Is needed for foods to be
digested and energy to be released for
your body to use.
AB
A+B
Activation Energy
• All reactions need energy to occur.
• Activation Energy – refers to the energy
needed to get the reaction started
For example, you must apply force when striking
a match to get the fire to start.
Activation Energy
Endothermic reactions – requires energy to be
absorbed to complete the reaction. Therefore there will
be more energy in the products than in the reactants
Notice in the diagram the different
energy levels between the reactants
and products.
Real life Example: photosynthesis –
reactants of water and CO2 and
energy from the sun (activation
energy) creates products of Glucose
and O2.
Activation Energy
Exothermic reaction- Requires energy to be released to
complete the reaction. Therefore, there will be less energy in
the products than in the reactants.
• Notice the different energy
levels between the reactants
and products.
• Example: combustion
reactions of fuels.
Catalysts

Catalyst - a substance that lowers a chemical reactions
activation energy
◦ In other words, speeds up the reaction.
Enzymes
Biological Catalysts are
called Enzymes.

They speed up chemical
reactions in the cells. However they
are not essential, for the reactions
can occur on their own

Enzymes
•The names of enzymes typically end in “-ase”
•For example: protease splits proteins into its monomers - amino
acids.
•What do you think carbohydrase does?
•Splits carbohydrates (polysaccarides) into its monomers monosaccarides.
•Also used for: protein synthesis, synthesis of RNA and DNA, etc.
Endothermic Reactions
• http://www.plms.issaquah.wednet.edu/teach
ers/abraham/PDF's/Exothermic%20and%20En
dothermic%20Reaction%20Lab%202009%20_
with%20data_.pdf