daily practice 10/13/09
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Daily Practice 10/13/09. What could you do different this quarter to improve your grade vs. 1 st quarter? What should you do if you miss an assignment? How many days do you have to complete it? Who’s responsibility is it to make up tests/quiz/assignments? - PowerPoint PPT PresentationTRANSCRIPT
Daily Practice 10/13/091. What could you do different this quarter
to improve your grade vs. 1st quarter?2. What should you do if you miss an
assignment? How many days do you have to complete it?
3. Who’s responsibility is it to make up tests/quiz/assignments?
4. Turn in any makeup/late work into the tray before the bell rings!!!!!!!!!!!!!!!!!
Ch. 2 The Chemistry of Life
Section 6.1
Atoms, Elements, and CompoundsObjectives•Identify the particles that make up atoms.•Diagram the particles that make up an atom.•Compare covalent bonds and ionic bonds.•Describe van der Waals forces.
Nature of Matter
• Chemistry is the study of matter.• Atoms – basic unit (building block) of
matter–100 million atoms side by side would
make a row about 1 cm long (width of a pinkie finger)
Nature of Matter–Subatomic particles that make up atoms
are:• Protons – positively charged•Neutrons – no charge, same mass as protons• Electrons – negative charge and in constant motion surrounding nucleus
–Nucleus – center of the atom that contains protons and neutrons
Nature of Matter• Atoms are Neutral –Atoms have equal number of electrons
and protons– Ex: O has 8e- and 8protons
8e- +8p+
0 charge–Atomic Number - # of protons in an atom of elements
Elements• Element – pure substance that consists
entirely of one type of atom–More than 100 elements are known–24 are commonly found in living
organisms–92 of which occur naturally.
O2Fe
NS
CaNa
Ne
Elements• Each element has a unique name
and symbol.• Usually 1 letter capitalized like C
for carbon• Some have 2 letters in this case
the second is lower case like in Ca for Calcium
• The periodic table is organized into:–horizontal rows, called periods–vertical columns, called groups.
• Each individual block in the grid represents an element.
• The table is called periodic because elements in the same group have similar chemical and physical properties.
Daily Practice 10/14/091. What does the atomic number tell you?2. What two subatomic particles must be
equal in a cell in order for it to be neutral?
3. What does the atomic mass tell you?4. How do you calculate the number of
neutrons?5. Just like yesterday find the Atomic #,
mass, number of neutrons, and make the electron configuration for Cu
Isotopes
• Isotopes – atoms of same element that differ in number of neutrons they contain– Isotopes are identified by mass number–Mass Number – sum of protons and
neutrons in nucleus of an atom
Isotopes– Isotopes – – Protium -1p and mass 1–Deutrium -1p and 1neutron and mass
2–Tritium – 1p and 2 neutrons and mass
3
– Isotopes have the same number of e-, all isotopes of elements have the same chemical properties
Radioactive Isotopes Nuclei are unstable
and break down at a constant rate over time.
UsesDetermine ages of
rocks and fossilsTreat cancer and kill
bacteria that causes food to spoil
Used as tracers to follow movements of substances with in organisms
When a nucleus breaks apart, it gives off radiation that can be detected and used for many applications
A pure substance formed when two or more different elements combine
Compounds are always formed from a specific combination of elements in a fixed ratio.
Compounds cannot be broken down into simpler compounds or elements by physical means.
H2O → 2:1→ 2:H and 1:ONaCl → 1:1 → 1:Na and 1:Cl
COMPOUNDS
Chemical Bonds• Ionic Bonds – formed when one or more
e- are transferred from one atom to another.
• That means there is an electrical attraction between two oppositely charged atoms or groups of atoms– Ion – positively and negatively charged
atoms
–Na Cl
• The elements identified as metals tend to donate electrons.
The elements identified as nonmetals tend to accept electrons.
Some atoms tend to donate or accept electrons more easily than other atoms.
Most ionic compounds are crystalline at room temperature and have higher melting points than molecular compounds formed by covalent bonds.
Chemical Bonds Conti. Covalent Bond – formed when e- are
shared between atoms.Atoms share 2e- = single covalent
bond H2O
Chemical Bonds Conti. Atoms share 4e- = double covalent bond
O2Atoms share 6e- = triple covalent bond
N2 Molecule – is a compound that
is held together with covalent bonds.
Diatomic Molecules – molecules are made of 2 of the same atoms
H2, O2, N2, F2,Cl2 , Br2, I2
Chemical Bonds Conti. Pg 155• Van der Waals Forces – slight attraction that
develops between oppositely charged regions of nearby molecules.–Van der Waals forces are not as strong as ionic
or covalent bonds, they can hold molecules together, especially when molecules are large.
– The strength of the attraction depends on the size of the molecule, its shape, and its ability to attract electrons.
Section 6.2
Chemical ReactionsObjectives•Identify the parts of a chemical reaction.•Relate energy changes to chemical reactions.•Summarize the importance of enzymes in living organisms.
Chemical Reactions and Enzymes Chemical Reaction – process that
changes one set of chemicals into another set of chemicals. (That is they are reorganized into different substances)
Ex: Fe + O2 → FeO2 (rust – slow process)
Ex: 2H2O → H2 + O2
Chemical Reactions and EnzymesClues that a chemical reaction has taken place include the production of heat or light, color change and formation of a gas, liquid, or solid.
Chemical Reactions and EnzymesReactant – elements or compounds
that enter into chemical reaction Ex: Fe + O2 and 2H2O
Product – elements or compounds produced by chemical reaction Ex: FeO2 and H2 + O2 Lab Demo – Baking Soda
Balanced EquationsThe law of conservation of mass states
matter cannot be created or destroyed.The number of atoms of each element on
the reactant side must equal the number of atoms of the same element on the product side.
Energy in Reactions Energy is released or absorbed when
chemical bonds form or break Chemical reactions releasing energy
occur spontaneously2H2 + O2 → 2H2OH gas burning with O2 = water vapor
with energy released in form of heat and if H explodes = light and sound
Humans release energy needed to grow, breathe, think, metabolize, break down food, or digest food
Energy in Reactions–Chemical Reactions absorbing energy will
not occur without source of energy• 2H2O → H2 + O2• Absorbs energy and must have electric current going through water• Plants get energy by trapping and storing energy from the sun• Animals get energy when they eat plants or animals that eat plants
–Activation Energy – energy needed to get reaction started• Lighting a match to burn trash
Energy in Reactions–Activation Energy – energy needed to
get reaction started• Lighting a match to burn trash
Energy in Reactions
This reaction is exothermic and released heat energy.
The energy of the product is lower than the energy of the reactants.
Energy in Reactions
This reaction is endothermic and absorbed heat energy.
The energy of the products is higher than the energy of the reactants.
Enzymes Catalyst – substance
that speeds up rate of chemical reaction or lowers reaction’s activation level It does not
increase how much product is made.
A catalyst is not used up in a reaction.
Enzymes Cont. Enzymes – proteins that act as biological
catalystsCells use enzymes to speed up
chemical reactions that take place in cells and lowers activation energy
P. 51 graphCarbonic anhydrase, enzyme in
bloodstream that speeds up reaction to remove CO2 (Carbon Dioxide) from blood
Enzyme Action For chemical reactions to occur then
reactants must collide with energy so bonds will be broken and new bonds formed
The reactants that bind to the enzyme are called substrates – (they help catalyzed reactants)Substrates (protein) that attach to
enzyme at active site and form an enzyme – substrate complex
Enzyme Action–The specific location where a substrate
binds on an enzyme is called the active site.–Proteins have a specific shape, so an
active site must be complementary–Compared to a lock and key model
The active site changes shape and forms the enzyme-substrate complex, which helps chemical bonds in the reactants to be broken and new bonds to form.
Enzyme Action–When complex is formed, enzyme helps
convert substrate into product until done and then they are released–Most cells contain proteins that turn
key enzymes on or off, along with pH and temperature•Human cells work best at 37⁰, human body’s core temperature
Section 6.3Water and Solutions
Objectives• Evaluate how the structure of water makes it a good solvent.•Compare and Contrast solutions and suspensions.•Describe the difference between acids and bases.
Properties of Water Water
Covers ¾ of EarthSingle most abundant
compound in most living things
Expands as it freezes and is less dense than liquid water explaining why it floats
Properties of Water Conti.• Water Molecules– H2O = 2protons H + 8protons O = 10 protons
2e- H + 8e- = 10e-10protons + 10 e- = 0 (neutral)
• Polarity–Water molecule is polar because there is uneven
distribution of e- between H and O2 atoms/• Between molecules is a magnet with poles• O2 end has negative charge and H end has + charge
Hydrogen Bonds• A hydrogen bond is a weak interaction
involving a hydrogen atom and a fluorine, oxygen, or nitrogen atom
Cohesion – attraction b/w molecules of same substance Water molecules can have up to 4
H bonds at the same timeCohesion is why drops of water
form beads on smooth surfaces
Hydrogen Bonds Adhesion – attraction b/w molecules
of different substances Water in graduated cylinder dips
at center b/c adhesion b/w glass and water molecules are stronger than cohesion of water molecules
Capillary action – forces draws water out of plant rot up to stems and leaves
Solutions and Suspensions Mixture – material
composed of 2 or more elements or compounds that are physically mixed together but not chemically combined.Ex: vegetable soup,
salt and pepper, Earth’s atmosphere gases
Homogenous MixturesA mixture that has a uniform composition throughout
A solvent is a substance in which another substance is dissolved.
A solute is the substance that is dissolved in the solvent. Food coloring dissolved in
water forms a homogenous mixture.
Heterogeneous Mixtures
In a heterogeneous mixture, the components remain distinct.
A salad is a heterogeneous mixture.
Solutions and Suspensions Conti. 2 types of mixtures made with water are
solution and suspensions.Solution (sol’n) – mixture of 2 or more
substances where the molecules of substance are evenly distributed Ex: table salt put into water
Solute – substance that is dissolved (table salt)
Solvent – substance where the solute dissolves (water)
Solutions and Suspensions Conti.Suspensions – mixture of water and
non-dissolved material Ex: blood is mostly water with many dissolved compounds)
Acids, Bases, pH - P. 164 pH scale – measurement system used to
indicate the concentration of Hydrogen ions (H+) in solution0 7 14
Acids – Substances that release hydrogen ions (H+) when dissolved in water0 6.9 = acidThe lower the number the stronger the
acid
Acids, Bases, pH - P. 164 Bases Substances that release
hydroxide ions (OH–) when dissolved in water 7.1 14 = baseThe higher the number the
stronger the base Buffers –are mixtures that can react
with acids or bases to keep the pH within a particular range.Fluids in human cells is 6.5 -7.5 to
maintain homeostasis.
Section 6.4
The Building Blocks of LifeObjectives•Describe the role of carbon in living organisms.•Summarize the four major families of biological macromolecules.•Compare the functions of each group of biological macromolecules.
Carbon Compounds Organic Chemistry – study of all
compounds that contain bonds between C atoms
Chemistry of Carbon (C)C atoms have 4 valence e-C’s atomic # is 6 (2e- in 1st shell, 4e- in
2nd shell)Each e- can join with e- from another
atom forming strong covalent bondsC can bond with H, O, P, S, N
C has the ability to form millions of different large and complex structures
C
Carbon Compounds Cont. One carbon atom can form four covalent
bonds with other atoms. Carbon compounds can be in the shape
of straight chains, branched chains, and rings.
C
Carbon Compounds Conti.• Macromolecules – giant molecules– Monomers – small unit that can join together with
other small units to form polymers– Polymers – large compound formed from combo of
many monomers– Monomers can be identical like metal links in watch
bands or different beads in multicolored necklace.– 4 groups of organic compounds found in living
things carbohydrates, lipids, nucleic acids, proteins
Carbon Compounds Conti. Carbohydrates (Carbs) –Compounds
composed of carbon, hydrogen, and oxygen in a ratio of one oxygen and two hydrogen atoms for each carbon atom; a ratio 1:2:1—(CH2O)nLiving things use carbs as main source
of energyStarches and sugars are carbs used as
an energy sourcePlants and some animals use carbs for structural purposes.
Values of n ranging from three to seven are called simple sugars, or monosaccharides.
Carbon Compounds Conti.• Monosaccharides – single sugar
molecules• Ex: Galactose – in milk and Fructose – in
fruit• Polysaccharides – large macromolecules
formed from monosaccharides • Glucose in blood runs low, glycogen is
released from your liver.• Glycogen – stored in muscles and supplies
energy for muscle movement• Plants use cellulose that gives them
strength and rigidity–Major component of wood and paper
Carbon Compounds Conti. Lipids – macromolecules made from C
and H atoms, including fats, oils, and waxesStore energyImportant parts of biological membranes and
waterproof coveringsSteroids are chemical messengers of lipidsA triglyceride is a fat if it is solid at room
temperature and an oil if it is liquid at room temperature
Lipids that have tail chains with only single bonds between the carbon atoms are called saturated fats.
Lipids that have at least one double bond between carbon atoms in the tail chain are called unsaturated fats.
Fats with more than one double bond in the tail are called polyunsaturated fats.
Carbon Compounds Conti.• Proteins – macromolecules containing
N,C, H, O– Proteins have specific roles• Control rate of reaction and regulate cell
processes• Form bones and muscles• Transport substances into and out of cells
to fight disease
Carbon Compounds Conti.– Proteins are polymers of amino acids• Amino acids – are small compounds that are made of carbon, nitrogen, oxygen, hydrogen, and sometimes sulfur.• 20 amino acids are found in nature & all may be joined together by covalent bonds• Amino acids are monomers of proteins• Amino acids have a central carbon atom.• One of the four carbon bonds is with hydrogen.• The other three bonds are with an amino group (–NH2), a carboxyl group (–COOH), and a variable group (–R).
The number and the order in which the amino acids are joined define the protein’s primary structure.
After an amino acid chain is formed, it folds into a unique three-dimensional shape, which is the protein’s secondary structure, such as a helix or a pleat.
Carbon Compounds Conti. Nucleic Acids – macromolecules
containing H, O, N, C, P Nucleotides – 5-Carbon sugar,
phosphate group, and nitrogenous base
Nucleic Acids store and transmit hereditary or genetic information 2 types – ribonucleic acid (RNA) and deoxyribonucleic acid (DNA)
Nucleic acids are made of smaller repeating subunits called nucleotides, composed of carbon, nitrogen, oxygen, phosphorus, and hydrogen atoms.