Download Basic Chemistry - Model High School

Elements & Atoms
I. Elements & Atoms
Element = A substance that cannot be
_________
broken down into simpler substances.
• Periodic Table
nature (natural elements)
• 1-92 occur in _______
synthetic (man• 93 and above are ___________
made)
Natural Elements:
Trace Elements:
25 are essential
____
to living things.
Found in very
small amounts
_______
but are _________
essential
to proper
activities.
Carbon (C),
Hydrogen (H),
Oxygen (O),
Nitrogen (N) make
up 96% of human
mass.
• Ex. Iron,
magnesium,
iodine
_______
ATOM = Smallest particle of an element
that has the characteristics of that element.
3 Subatomic particles make up an atom:
Protons (p+) = positively
1. _______
________ charged particles
Neutrons (n) = no charge (_______)
neutral
2. ________
3 Subatomic particles make up an atom:
negative charge) move
Electrons (e-) = (________
3. ________
nearly at the speed of light ; form a cloud
around the nucleus
2 parts of an atom:
Nucleus = center of atom; contains
1. ________
protons & _________.
neutrons
________
Electron cloud/energy levels
2. ______________________________
=
around the nucleus
o Atoms contain an equal number of
electrons
________
protons and ___________
so the
zero
overall charge of an atom is ______.
II. Isotopes:
Isotopes = Atoms of the same
o __________
element that have different numbers
neutrons
of ________
II. Isotopes:
atomic mass numbers
o Named by their ____________________
o C-12 = _____
6n + 6p+
7n + 6p+
o C-13 = _____
o C-14 = _____
8n + 6p+ → radioactive
III. Atomic Number & Atomic Mass
Atomic Number = number of _______
protons
o ______________
electrons of an atom.
and/or _________
o Ex.
Na-23 contains 11 electrons and 11 protons
Mass Number = the _____
sum of protons
o ______________
and neutrons in an atom.
+) + # of neutrons (n)
#
of
protons
(p
o ___________________________________
IV. Energy Levels & Diagramming Atoms:
Energy Levels
o _______________
= regions around the
nucleus that electrons travel.
_________
o 1st energy level can ONLY have 2 electrons
(except Hydrogen, it has only 1 e-)
IV. Energy Levels & Diagramming Atoms:
Octet Rule = each energy level AFTER
o ____________
8 electrons.
the first can have up to ___
o The 3rd energy level has 18 e-
o What atom is
represented in
this picture?
Sodium (Na)
o ___________
8
o How do you know?
o ___________________________________
Sodium’s atomic number is 11 so it has 11 e-.
Example: Helium (He)
Atomic # = 2; Mass # = 3
2e2p+
1n
nucleus
Example: Chlorine (Cl)
Atomic # = 17; Mass # = 35
17p+
18n
7e2e8e-
Example: Carbon (C)
Atomic # = 6; Mass # = 14
2e6p+
8n
4e-
Interactions of Matter
I. Compounds and Bonding:
o __________
Compound = a substance made of
chemically combined elements.
o Atoms bond to form
__________________
stable compounds
o Atoms need _____
8 e- in OUTER energy
level to be stable;
Exception: hydrogen & helium need 2e-
Open bonding sites
(electrons) encourage
bonding
_________.
I. Compounds and Bonding:
o Elements can combine in two ways”
Covalent Bonding
1. __________________:
SHARE electrons
Covalent bonds ________
The positively charged nucleus is
attracted to the negatively
___________
charged electrons.
Water, sugars, fats and proteins are
covalent molecules
____________________
Covalent Bond: occurs between nonmetals
Examples
of
Covalent
Bonding
Van der Waals Forces:
I. Compounds and Bonding:
Molecule = a group of covalently
o __________
bonded atoms with ___
no charge.
o Ex: H2O 2 hydrogen atoms + 1 oxygen atom
two
o Oxygen needs _____
electrons to become stable
one
o Each hydrogen needs ____
electron to fill orbital
SHARE
o Therefore, they ________!!
I. Compounds and Bonding:
Ionic Bonding
2. _______________:
__________
TRANSFER of electrons creating ions
Ionic Bond
that attract each other = ____________
I. Compounds and Bonding:
Ions = charged atoms because they
o ______
have ________
gained or ______
lost electron(s)
lose electrons become
o Atoms that ______
positive
more _________
gain electrons become
o Atoms that ______
more _________
negative
o Atoms gain/lose electrons efficiently
Ionic Bond: occurs between metals and nonmetals
Ions in living things:
o Include - ________,
sodium potassium, calcium,
chloride, carbonate ions.
o Help maintain _____________
homeostasis as these
ions travel in and out of cells.
signals among cells
o Help transmit _________
that allow you to see, taste, hear, feel and
smell.
I. Compounds and Bonding:
GAIN an electron
o More effective to ______
LOSE an electron!!
than to ______
II. Water is Polar:
Polar = unequal distribution of
o _______
charge
positive
o Each molecule has a __________
end
negative end.
and a __________
II. Water is Polar:
o Ex: Water (H2O) molecule  Oxygen
is much stronger and therefore has a
negative charge
stronger ________________
than the
hydrogen’s positive charge.
II. Water is Polar:
o Because of water’s polarity, it can
dissolve many ionic compounds
__________
and other polar compounds such as
sugars
________.
II. Water is Polar:
o The water molecules
adhere to each
also ________
other because of
polarity (unequal
__________
distribution of charge)
o The attraction of
opposite charges
weak bond
forms a ______
called a
hydrogen bond
_______________.
together
o This keeps large molecules __________!
o (Ex: proteins)
III. Uniqueness of Water – due to its polarity
Cohesion = the attraction between like molecules
1. _________
Surface tension
• _________________
results from the cohesive
properties of water.
• The polarity of water
causes the surface layer
of water molecules to
act like a stretched film
over the surface of the
water (______________)
surface tension
Ex. Water striders
III. Uniqueness of Water – due to its polarity
2. Creeps up in thin tubes
(capillary action)
________________
• The polarity of water
plants to get
allows _______
water from the
ground
________.
• Water creeps up tubes in
plant roots and stems.
III. Uniqueness of Water – due to its polarity
Expands when it freezes
• _________________________
less dense than water (ice floats)
• Ice is _____
Water is Less Dense as a
Solid
•Which is ice and which is water?
Water is Less Dense as a
Solid
Water
Ice
Chemical Reactions
Examples of chemical reactions
I. Chemical Reactions:
o All the chemical reactions in our
metabolism
bodies are called ____________.
o Breakdown and reassemble molecules in
the body.
Chemical Bonds are
________________
broken and formed during
chemical reactions.
II. Writing a Chemical Equation:
II. Writing a Chemical Equation:
• ______________
= # of molecules
Coefficient
of a compound
• Ex: 6O2 = 6 molecules of Oxygen (O)
3 molecules of H2O
• 3H2O = ___
CH4 + 2O2  CO2 + 2H2O
II. Writing a Chemical Equation:
• _________
Subscript = # of atoms of an element
• Ex: CH4 = 1 atom C, 4 atoms H
1 atom of C, ___
2 atoms of O
• CO2 = ___
CH4 + 2O2  CO2 + 2H2O
II. Writing a Chemical Equation:
• How many atoms of O are in 6O 2?
12 atoms of O!
____
III. Balancing Chemical Equations:
same
• In ALL chemical equations the ______
number of atoms of elements are on the
reactant and product side of chemical
equations.
•
Why?
Law of Conservation
• Because the _________________________
of Matter
_____________
(atoms are never created
or destroyed; they are simply rearranged)
III. Balancing Chemical Equations:
• We balance equations so the Law of
Conservation of Matter is NOT
violated
__________!
• We must always balance equations using
coefficients
____________!!
III. Balancing Chemical Equations:
Subscripts can never be changed!
• ____________
• Coefficients must always be place in
FRONT of the entire compound!
_______
• Create an atom inventory.
Ex: Balance the following equations so the Law of
Conservation of Matter is NOT violated:
2 H 2 + O 2  2 H 2O
Ex: Balance the following equations so the Law of
Conservation of Matter is NOT violated:
CaO + 2KBr 
K2O + CaBr2
Ex: Balance the following equations so the Law of
Conservation of Matter is NOT violated:
Al2S3 +3 BaCl2  2 AlCl3+ 3BaS
Energy of Reactions
IV. Energy of Reactions:
o The key to a
chemical reaction is
energy
________!
o Most compounds in
living things
cannot undergo
________
chemical reactions
without energy.
IV. Energy of Reactions:
Activation Energy =
o ________________
the minimum amount
of energy needed for
reactants to form
products in a chemical
reaction.
Graph A
o Look at Graph A:
the peak in the graph
represents the amount
energy that must be added to the
of ________
system to make the reaction occur.
IV. Energy of Reactions:
o All living things are chemical factories
driven by _________________!
chemical reactions
o Enzymes (catalysts) need to be present
reduce the activation
in order to ________
energy and allow the reaction to
proceed quickly.
IV. Energy of Reactions:
o Look at Graph B:
the enzyme
lowers the
________
activation energy
and the product
will be formed
sooner!
Graph B
IV. Energy of Reactions:
Catalyst = a substance that lowers
o __________
the activation energy needed to start a
chemical reaction.
Enzyme = special proteins that are
o ________
biological catalysts that speed up the
rate of the chemical reaction.
o Essential to life!
Specific to one reaction.
o __________
How do ENZYMES work?
o The reactants that bind to the enzyme
substrates
are called ____________.
o The specific location where a substrate
binds on an enzyme is called the
active site
____________.
How do ENZYMES work?
o The active site and substrate have
complementary shapes (lock-and-key).
_______________
very specific for the
o Enzymes are ______
substrates that will change!
How do ENZYMES work?
o When the enzyme-substrate complex
broken and
forms, chemical bonds are ________
form to produce the
new bonds ______
products.
o Enzyme releases the _________
product and the
enzyme can be used again.
Factors that Affect Enzymes:
pH (how acidic or basic a substance is)
1. ____
2. _____________
Temperature
• Most enzymes in humans cells are
most active at 98.6oF
denature
• pH & temperature will __________
(change the shape) of the enzyme so it
will not be able to bond with the
corresponding substrate!
Examples of Enzymes Working:
digestion
1. Helps with ___________
replication
2. DNA ___________
3. Enzymes in the venom
of a venomous snake
break down the
____________
membranes of a
person’s red blood cells.
Examples of Enzymes Working:
ripen because of
1. Hard green apples _______
the action of enzymes
2. Photosynthesis and cellular respiration
energy for the cell with the
provide ________
help of enzymes
Enzymes
• The human body has over 1,000 types of enzymes.
• Each kind does one specific job.
• Without enzymes, a person could not breathe, see,
move, or digest food.
• IN SIMPLE LANGUAGE, ENZYMES KEEP US ALIVE!
• They regulate the digestion of our food, the
production of energy, the production of hormones
and other important body secretions, and the
destruction of foreign substances.
Examples of Enzymes
In the Human Body:
• Amylases - Amylases break down starch chains
into smaller sugar molecules. Your saliva contains
amylase and so does your small intestine.
• Lactase – break simple sugars down into
individual glucose molecules. (lactose
intolerant people don’t have this enzyme)
• Lipases - Lipases break down fats.
• Cellulases - Cellulases break cellulose
molecules (from plants) down into
simpler sugars. Most animals don’t
have these so we depend on bacteria
in our gut (approximately 3 lbs)
to help us do this.
Examples of Enzymes
Other enzymes:
•Proteases and peptidases Proteases and peptidases
are often found in laundry
detergents -- they help
remove things like blood
stains from cloth by
breaking down the proteins.
Regulation of Enzyme Activity
Temperature, pH, and regulatory molecules
can affect the activity of enzymes.
•Enzymes produced by human cells work
best at 98.6oF with a pH around 7.2.
•Pepsin in the stomach works best under
acidic conditions.
•Most are regulated by molecules that
switch them “on” or “off” as needed.
pH, Acids, Bases
V. pH, Acids, Bases:
o ____
pH = how acidic or basic
a substance is
o ______
Acid = substance that
forms H+ (hydrogen ions)
in water
water
HCl  H+ + Clless than 7)
(pH ______
V. pH, Acids, Bases:
Base = substance that
o ______
forms OH- (hydroxide ions)
in water
water
NaOH  Na+ + OHmore than 7)
(pH ______
The pH Scale
Measurement system to indicate the
concentration of H+ ions in solution.
Ranges from 0 to 14
pH 7 = neutral