Chapter 2
The Chemistry of Life
Section 1 Vocabulary Pretest
1. Matter7. Neutron13. Compound
2. Mass8. Atomic Number14. Chemical bond
3. Element9. Mass Number15. Covalent bond
4. Atom10. Electron16. Molecule
5. Nucleus11. Orbital17. Ion
6. Proton12. Isotope18. Ionic bond
Chemistry of Life
*All life activities in our cells are the result of ______
*The elements that make up living things are essential to life.
*______is anything that has mass and takes up space.
a. ______is the ______of matter in an object.
b. ______is the ______produced by gravity acting
on mass.
Elements
*______are substances that cannot be broken down
chemically into simpler kinds of matter.
- The Periodic Table lists over ______known elements
- About ______of these are important to living things.
- The 4 most common elements in living cells are: HONC “honk”
- ______--59% of cells. (mostly in the form of water)
- ______--24% of cells. Necessary for cellular respiration.
- ______-- 4% of cells. Key element in growth
- ______--11% of cells. Found in all organic cmpds.
Atoms
*An ______is the simplest particle of an element that ______
all of the ______.
*Parts of an atom
1. ______--center of atom. Contains 2 subatomic particles:
a. ______--positively charged
b. ______--no charge
2. ______---negatively charged particles that orbit the nucleus.
*The ______is the number of ______in an atom.
*The ______is the number of ______PLUS
the number of ______.
*The number of electrons in an atom is the same as the number of protons,
giving it a net charge of ______.
Isotopes
*______--atoms of the ______element with ______
number of neutrons. This gives them a different ______.
*Average Atomic Mass is the average of all of the ______of that element.
Models of Atoms (LABEL EACH)
______
*On the Bohr model, electrons are seen in ______called
______consisting of orbitals around the nucleus.
- Electrons that are ______from the nucleus have
______than those that are closer to the nucleus.
- Each energy level can only hold a certain number of electrons.
1st shell holds ______electrons4th shell holds ______electrons
2nd shell holds ______electrons5th shell holds ______electrons
3rd shell holds ______electrons6th shell holds ______electrons
Compounds
*Compounds are atoms of ______elements joined by
______
*Examples:
Chemical Bonds
*Chemical bonds are attractive forces that hold atoms together
*Bonds are determined by the ______of electrons in
the outerorbital of an atom.
*Atoms prefer to be ______(highest energy level is filled)
*Stable elements are known as ______or Inert Elements. They
______usually react with other elements.
*Found on ______side of Periodic Table.
* Other elements are ______, so they form chemical bonds to fill their
outer energy levels.
*Types of Chemical Bonds
1. Convalent Bonds—two atoms ______one or more pairs of electrons.
a. Examples:
b. ______has the ability to form multiple covalent bonds.
c. Many biological molecules form double and triple covalent bonds.
2. Ionic Bonds—based on attracted positive and negative charges on atoms.
a. Charges are created when an atom either loses an electron
(creating a ______charge) or gains an electron
(creating a ______charge)
b. Atoms with an electrical charge are called ______.
c. Example:
Section 2 Vocabulary Pretest
1. Energy5. Metabolism9. Redox Reaction
2. Chemical Reaction6. Activation Energy10. Oxidation Reaction
3. Reactant7. Catalyst11. Reduction Reaction
4. Product8. Enzyme
Energy
*Energy is the ability to ______
*Forms of energy important to living things include:
1. ______
2. ______
3. ______
4. ______
*Living things can ______one form of energy into another
States of Matter
*Three states of matter:
1. ______--fixed volume and shape
2. ______--fixed volume; takes shape of container
3. ______--takes the shape and volume of its container
Energy and Chemical Reactions
*Chemical reactions occur when one or more substances ______
one or more new substances.
*______show what happens during the reaction.
6CO2+ 6 H2O C6H12O6 + 6O2 +energy
*Reaction Speed
a. ______—energy required for a reaction to begin
b. ______--substances that speed up chemical
reactions by ______the activation en energy required.
c. ______are common catalysts in living things. They remain
______throughout the reaction.
Endothermic and Exothermic Reactions
*Endothermic reactions—result in a net ______of energy.
*Exothermic reaction—result in the net ______of energy.
Oxidation Reduction Reaction
*Also called ______
*Electrons are ______between atoms.
1. Oxidation Reaction—a reactant ______electrons resulting in a
______charge.
Ex:
2. Reduction Reaction—a reactant ______electrons resulting in a
______charge.
Ex:
Section 3 Vocabulary Pretest
1. Polar7. Solute13. Hydronium Ion
2. Hydrogen Bond8. Solvent14. Acid
3. Cohesion9. Concentration15. Base
4. Adhesion10. Saturated Solution16. pH scale
5. Capillarity11. Aqueous Solution17. Buffer
6. Solution12. Hydroxide Ion
Water and Solutions
*Water’s chemical structure is important in its vital role in life.
*Two hydrogen atoms covalently bonded to one oxygen atom.
a. The hydrogen and the oxygen ______electrons.
b. The electrons are not shared ______.
c. Oxygen pulls ______. Thus one side has a partial ______
charge and the other has a partial ______charge.
Draw diagram:
*A molecule like this is called a ______compound. The bonds are callled
______bonds.
*Being polar allows water to dissolve:
a. Other polar substances like ______
b. ______like salts
c. Some ______
*Water cannot dissolve ______such as oil.
Hydrogen Bonding
*Hydrogen bonds occur between a hydrogen molecule with a ______
and another atom or molecule with a ______.
*They allow water to “ ______” to itself. (Cohesion)
*Break and ______constantly
*Number of hydrogen bonds in water depends on the ______.
Solid-______
Liquid-______
Gas-______
*Hydrogen Bonds are responsible for:
1. ______—attractive force that holds molecules of a single
substance together. Ex:
2. ______—cohesive forces pull surface molecules down,
creating a thin “skin” on the surface. Ex:
3. ______—attractive forces between two particles of
different substances. Ex:
4. ______—rise of the surface of a liquid when in contact with
a solid. Ex:
Hydrogen Bonds and Heat Capacity
*Water can absorb or release a large amount of energy as heat.
1. Energy is ______to break hydrogen bonds
2. Energy is ______when hydrogen bonds form.
*This impacts living things in several ways:
1. ______
2. ______
3. ______
Solutions
*______—mixture in which one or more substances are
______in another substance.
*Related terms:
- ______—dissolved substance
- ______—substance in which the solute is dissolved
- ______—amount of solute dissolved in a fixed amount of solution.
- ______—no more solute can be dissolved
*______—solutions in which water is the solvent. They are vital to all living things. Ex: ______
______
______
Suspensions and Colloids
*______—mixture in which particles spread through a liquid
or a gas but settle over time. Ex:
*______—mixtures in which particles do not settle out over time.
Ex: ______
In liquid form = ______
In semisold form = ______
Ionization of Water
*Water molecules can collide and break each other apart:
______is known as the hydroxide ion
Free H+ ions react with water molecules:
______is known as the hydronium ion
Acids and Bases
*Acid—solution in which the number of ______is greater than the
number of ______
They have a value ______on the pH scale.
*Base—solution in which the number of ______is greater than the
number of ______( )
They have a value ______on the pH scale.
Buffers
*Living things must be able to control pH
*Buffers—chemical substances that ______small amounts of either an acid
or a base.
*Many complex buffer systems in living things to balance their fluids.
Ex: