Chapter 2 Chemistry of Life

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Chapter 2 Chemistry of Life

• Can you list the levels of organization?

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Matter

• Matter Anything that has mass and takes up
  space made up of atoms.
• States of matter
• Solid has definite shape and volume
• Liquid has definite volume, changeable shape
• Gas has changeable shape and volume

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Understanding Basic Chemistry

• Atom the smallest particle into which a
  substance can be broken by ordinary chemical
  means.
• Parts of an Atom
• Proton in the nucleus and has a positive charge
• Neutron in the nucleus and has a neutral charge
• Electron in the orbital (shell, energy level)
  and has a negative charge

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• Atomic Mass protons neutrons
• Atomic Number protons
• Electrons usually equal the protons if the atom
  is neutral.
• Remember an atom is defined by its number of
  protons. If you change the protons you change
  the atom!!!!!!!!

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• Valence number of electrons in the outer energy
  level. Example 7
• Oxidation Number number of electrons an atom
  has gained or lost and the charge associated.
  Ex. Looking at the above valence of 7 the
  oxidation number is -1
• Octet Rule - filling the outer energy level to 8
  electrons (exception is the first energy level
  that can only hold two electrons)

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Levels Reviewed

• Atom - The smallest particle into which a
  substance can be broken by ordinary chemical
  means.
• Remember an atom has a nucleus that consists of
  neutrons (neutral) and protons (positive)
• Electrons (negative) are found orbiting the
  nucleus

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Element Groups of the same type of
atom Molecule- Groups of non metal atoms bonded
together by covalent bonds acting as a group.
Compound Two or more elements chemically
combined ex. H2O
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• (Organelles- Basic structures within cells has
  a specific function) (remember on the line not on
  a step?)
• Cell - Basic Unit of living things.

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• Tissue- Tissues are groups of the same cells
  they have a common function.
• Organ- Composed of several different tissues
  working together.

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• Organ system - A group of organs working
  together to perform a major body process. Ex.
  Digestion.
• Organism- (a group of organ systems in an
  individual) any living thing this would be
  multicellular (more than one cell)

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• Population - (1 species ex. squirrels)
• Community - (2 or more species ex. Squirrels and
  maple trees)
• Ecosystem - (biotic and abiotic - meaning all
  the living and nonliving things in an area)
• Biome - (regional or global area ex. The tundra
  or a rain forest)
• Biosphere - the earth.

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General Chemistry You Should Remember ?
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Mixtures

• Mixtures two or more substances not chemically
  combined therefore they retain their own
  properties

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Types of Mixtures

• 1. Solutions evenly combined mixture composed
  of
• Solvent does the dissolving ex. Water
• Solute the substance being dissolved ex. Sugar

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• 2. Suspensions The particles will spread out
  and eventually settle large particles
  (saturated, unsaturated, and supersaturated)
• Example sand in water (whole blood)
• 3. Colloid a mixture that has medium particles
  held in solution by their association with
  water
• ex. Liquid jello.. Mayonnaise

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Mixtures Compared with Compounds

• No chemical bonding takes place in mixtures
• Most mixtures can be separated by physical means
• Mixtures can be heterogeneous or homogeneous
• Compounds cannot be separated by physical means
• All compounds are homogeneous

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Writing Chemical Equations

• The left side of an equation is called the
  reactants.
• The right side of an equation is called the
  products
• An arrow separates the reactants from the
  products. The arrow is called a yields sign
• Ex. Na Cl ? NaCl

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TYPES OF BONDS(Bonds store energy)

• IONIC BONDS- ELECTRONS ARE TRANSFERRED FROM ONE
  ATOM TO ANOTHER AND IONS ARE FORMED
• Ions are charged atoms resulting from the gain or
  loss of electrons
• Anions have gained one or more electrons (taking
  is negative)
• Cations have lost one or more electrons (giving
  is positive)

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Covalent bonds- when atoms share electrons (the
strongest bond) e.x. Peptide bonds between C
and N in proteins
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Hydrogen bonds- a bond between hydrogen and 2
small electronegative atoms ex. f, n, o (the
weakest bond and remember it is really an
attraction.
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Polar and Nonpolar Covalent Molecules
Electrons shared equally between atoms produce
nonpolar covalent molecules Unequal sharing of
electrons produces polar covalent molecules (ex.
Water!) (unequal causes a charge on each
molecule)
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Types of Reactions

• Chemical Reactions the process of breaking down
  chemical bonds and/or forming new ones (a
  chemical equations shows this)
• To do this an activation energy is needed ( the
  energy that is needed to get the reaction going)
• Exothermic there is a net release of energy (it
  feels warm)
• Endothermic there is a net absorption of energy
  (feels cool)

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Type of Reaction Definition ? Equation
Synthesis
Decomposition
Single Replacement
Double Replacement
Two or more elements or compounds combine to make
a more complex substance (ex. Dehydration
synthesis takes H2O away)
A B ? AB
AB ? A B
Compounds break down into simpler substances (ex
hydrolysis puts H2O back)
Occurs when one element replaces another one in a
compound
AB C ? AC B
AB DC ? AC DB
Occurs when different atoms in two different
compounds trade places
A Red B Blue C Green D Yellow
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Additional Vocabulary

• 1. Dehydration synthesis (condensation) the
  formation of complex molecules by the removal of
  H2O

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• 2. Anabolism Energy requiring building phase
  of metabolism in which simpler substances are
  combined to form more complex substances

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• 3. Hydrolysis is an example of a decomposition
  reaction where water is added back into the
  molecule

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• 4. Catabolism Process in which living cells
  break down substances into simpler substances

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SUMMARY

• The Atomic Number of an atom
• number of
• protons in the nucleus. (or electrons in a
  neutral atom)
• The Atomic Mass of an atom
• number of Protons Neutrons in the nucleus.

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• Remember
• Protons are positive,
• Neutrons are neutral
• electrons are negative.
• 4. Protons, Neutrons are in the nucleus and
  electrons are in the shell.

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• 5. The number of Protons
• Number of Electrons in a neutral atom or the
  atomic number.
• 6. A normal atom has a neutral charge
• 7. An atom that has given or taken electrons is
  called an
• ion (cation gave.. Anion took)
• 8. An atom that has a different number of
  neutrons is called an
• isotope

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• 9. Electrons orbit the nucleus in shells/energy
  levels/orbitals.
• 10. Each shell can only carry a set number of
  electrons

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• 11. Valence number of electrons in the outer
  energy level. Example 7
• 12. Oxidation Number number of electrons an
  atom has gained or lost and the charge
  associated. Ex. Looking at the above valence of
  7 the oxidation number is -1
• 13. Octet Rule - filling the outer energy level
  to 8 electrons (exception is the first energy
  level that can only hold two electrons)