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General facts
- matter is in the realm of anatomy
- energy is in the realm of physiology
- chemistry is the gross anatomy of physical sciences
- physics is physiology
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Matter
- world is made up of matter
- occupies space
- has mass/weight
- has variable states - gas, solid, liquid
- state is determined by the energetic state of atoms
- can transition from one state to another based on energy
- water + energy = gas
- water - energy = solid
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Atoms
- fundamental units of matter
- composed of smaller units - protons, neutrons, electrons
- arranged in a specific order - nucleus, electron cloud
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Electrons
negative charge
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Nucleus
contains protons and neutrons
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Electron cloud
- contains electrons
- electrons have different energy levels/shells/orbits
- 1st shell has at most 2 electrons
- other shells have at most 8 electrons
- each shell must be full before the next one can have electrons
- if outermost shell is full, atom is not reactive
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Elements
- made of atoms of the same type
- cannot be broken down into any other substance
- 112 (may be 119 now) elements - 92 of them occur in nature
- examples: gold, oxygen, carbon
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Chemical Symbol
- derived from Greek, Latin or English name
- O = oxygen
- AU = aurum (gold)
- Ag = argentium (silver)
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Atomic Weight
sum of # of protons and neutrons in the nucleus
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Atomic Number
number of protons present
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Biologically important elements
- O = Oxygen
- C = Carbon
- N = Nitrogen
- K = Potassium (Kali, greek)
- Na = Sodium (Natrum, latin)
- Cl = Chloride
- S = Sulfur
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Periodic Table
- last column is noble gases - inert; don't react; outer shell full
- rows and columns are closely related in behavio (how they react chemically)
- in cats?, acetominophen binds irreversibly to hemoglobin so it can't carry Oxygen
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Sub-Atomic particles
- neutrons and protons
- sub-atomic level is where chemical binding occurs
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Neutrons
- found in nucleus
- neutral in charge
- along with protons, have mass and contribute to atomic weight
- proved to exist as atomic weight is 2x the number of protons
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Protons
- found in nucleus
- positive charge
- equal in number to neutrons
- mass = one (arbitrarily set)
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Electrons
- extremely small particles
- little atomic mass
- orbit the nucleus in electron shells
- negatively charged
- credit the net electrical charge of an atom
- most atoms neutral - protons = electrons
- sometimes form ions
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Ions
- atom carries a charge
- positive - fewer electrons than protons
- negative - more electrons than protons
- are reactive
- in body they are called electrolytes
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Isotopes
- proton # is constant
- neutron # is different
- causes variation in atomic weight, but not in charge
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Three isotopes of Hydrogen
- Protium - 1 proton, no neutrons
- Deuterium - 1 proton, 1 neutron - normal hydrogen
- Tritium - 1 proton, 2 neutrons
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Radioactivity
- defined by isotopes
- can measure age by rate of decay (change in weight of atom)
- half life can be short - water, cessium
- half life can be tens of thousands of years - uranium
- eg carbon dating
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Molecules and Compounds
chemical joining of atoms create molecules and compounds
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Molecule
- joining of two or more atoms
- if same kind of atom, it is a molecule of the element
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Compound
- if different kind of atoms join, it is a compound
- sodium + chloride = sodium chloride
- all compounds are molecules
- not all molecules are compounds
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Chemical bonds
- occur when atoms share or transfer electrons between themselves
- vary in strength
- three types - covalent, ionic, hydrogen
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Covalent bonds
- strongest
- atoms share electrons
- carbon is great sharer of electrons (makes strong bonds)
- very difficult to break
- strength depends on number of shared electrons - one=single, two=double, three=triple
- like happily married person not even looking at other pootential mates
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Polar molecules
- covalent bond
- molecule shares electrons unequally
- creates a positive and negative end (on the molecule, not the individual atoms)
- molecule itself is not charged
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Ionic bonds
- electrons transferred from one atom to another
- usually involve atoms that have almost full and almost empty outer shells
- drawn together by electrostatic attraction
- participating atoms become ions (charged particles)
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Ions
- atoms that carry an electrical charge
- participate in ionic bonding
- important to the body in muscle contraction, nerve impulses, and water balance
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Cations
positively charged ions
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Anions
negatively charged ions
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Ionic Bonds
- not strong enough to be polar
- weaker than covalent bonds
- atoms tend to stay together unless something more attractive comes along
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Hydrogen bonds
- special type of ionic bond
- occur between hydrogen atoms already bonded to other atoms covalently
- hydrogen has atomic # of 1; will either pick up 1 or give up 1 electron
- very weak bond - will break at the drop of a hat
- important to proteins
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Chemical reactions
- formation and breaking of chemical bonds
- we are chemical in our most basic state
- reactants combine to form products
- 3 types of reactions - synthesis, decompostion, exchange
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Chemical Equation
- written description of chemical reaction
- reactants - eg X and Y
- products - eg Z
- arrow direction indicates type of reaction
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Synthesis reactions
- build things up
- eg CO2 + H2 -> CO + H2O
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Decomposition reactions
- break things down
- eg AB -> A + B
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Exchange reactions
- no net change
- most common is buffer reaction, eg when you drink OJ your blood doesn't get acidic
- eg NaHCO3 + HCl <=> NaCl + H2O + CO2
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Energy and Chemical reactions
- synthesis reactions require energy which is then stored in the chemical bond
- decompostion reactions release energy in several forms - heat, light, radiation
- exchange reactions are energy neutral - energy in = energy out
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Rate of Chemical reactions
- concentration of reactants
- temperature - heat increases rate of reactions
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Activation energy
amount of energy required to start a chemical reaction
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Catalysts
- help speed reactions but don't take part in them
- catalyst can be reused
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Enzymes
protein catalysts found in nature
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Whelping problems
- babies not coming out
- 1st thing to do is give calcium & glucose to aid muscle contraction
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Nerve conduction
requires sodium and potassium
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Muscle cramps
need potassium
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Fresh food vs older food
- fresh (dry) food is important
- food has micronutrients that are important as catalyst
- older food will have less micronutrients so animal may become ill
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Inorganic Compounds
- do not contain hydrocarbon groups (hydrogen and carbon molecules bonded together)
- often bound by ionic bonds
- important ones include - water, salts, acids and bases
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Organic Compounds
- contain hydrocarbon groups (hydrogen and carbon molecules bonded together)
- usually contain covalent bonds
- common ones (all food) - carbohydrates, lipids, proteins, nucleic acids
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Functional Groups in Organic Compounds
- A group of atoms that defines the properties of an organic molecule
- allows for differences between molecules with similar hydrocarbon structures
- eg housing development w/ houses all the same; one owner adds chimney, another shrubs, etc
- eg galactose, sucrose, lactose are all sugars
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Water
- inorganic compound
- polar molecule - chemically neutral w/ positive and negative end
- universal solvent - even rocks will eventually yield
- ideal transport medium
- high heat capacity - takes a lot of energy to change state of water
- high heat of vaporization
- lubricating - reduce friction
- can't survive > 3 days w/o water
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Solutes
chemicals added to water
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Hydrophilic
- water lover
- mix well with water
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Hydrophobic
- water hater
- non-polar, neutral molecules like lipids
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Salts
- composed of minerals
- bound by ionic bonds
- principal form of mineral storage in the body
- eg potassium salts, calcium salts, phosphur salts (storage of phosphates)
- capable of ionization - electrolytes
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Acids
- freely release hydrogen ions
- proton donors
- H+
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Bases
- freely accept hydrogen ions
- proton acceptors
- OH-
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Acids and Bases
- neutralize each other
- important when we have stupid human tricks - eg dog eats Tidy Bowl; give vinegar
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pH Scale
- measures alkalinity and acidity
- ranges 1-14
- 7 is neutral (pure water)
- 1 is most acidic
- 14 is most basic
- dogs skin is different pH from humans
- cats & dogs are different also
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Buffers
- weak acids and bases that do not completely ionize in water
- help keep pH in the neutral range during chemical reactions in living systems
- in lactated ringers - lactate is a buffer
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