Chapter 1: The Metric System

The metric system offers simplicity and basic units.  

Physical Quantity SI basic unit SymbolLength Meter

mMass Gram gTime Second sTemperature Kelvin K

Celsius CVolume Liter LAmount of substance mole mol

Chapter 2- The Chemical Basis of Life

I. Nature of Matter

A. Elements1. Matter: anything that occupies space and has mass2. Element: is a pure substance that can not be broken down into other substances

a. Example: Na = sodium Cl = Chlorine H = Hydrogen O = Oxygen

3. Compound: is a group of elements that are chemically joined together to create a new substancea. Example: NaCl = sodium chloride or table salt and

H2O = water

b. Compounds will have different physical and chemical properties than those of the single element.

4. There are 25 essential elements that are necessary for life. The 1st 4 elements make up 96% of the matter in your body. Oxygen = O Carbon = C Hydrogen = H Nitrogen = N Calcium = Ca Phosphorus = P Magnesium = Mg Potassium = K Sulfur = S

5. Trace Elements make up less than 0.01% of your body mass. They are very important for your health. a. Trace Elements include:

Iron = Fe, Sodium = Na, Chlorine = Cl, Iodine = I,

Copper = Cu, Fluorine = F, Manganese = Mn , Selenium = Se

6. Mnemonic Device for the 11 major elements of life: Mg, Ca, Fe, S, H, O, P, I, N, C, K Example: C. HOPKINS CaFe Mg C. Hopkins café (is)

mighty good.

B. Compounds1. Most elements interact act with other elements

to form compounds2. When elements combine, they will be in a fixed

ratio

a. For example, a water molecule (H2O) always has 2 hydrogen atoms attached to 1 oxygen atom

C. Atoms1. Each element consists of a single kind of atom

and this atom is different than all other elements2. Atom: smallest piece of matter 3. Made up of 3 subatomic particles: proton (+),

neutron (no charge) and electron (-)

a. Protons i. Positive chargeii. Found in the nucleus( or center) of the

atomiii. The # of protons in the atom determines

the type of element. This number is called the atomic number.

b. Neutronsi. Neutral/no chargeii. Found in the nucleus of the atomiii. Usually the #of protons = the #of

neutronsiv. The atomic mass = # of neutrons + # of

protons

.c. Electrons

i. Negative chargeii. Located in the electron cloud outside the

nucleus, always movingiii. Very small, very little massiv. An atom with a net charge of zero, will

have the same #of protons & electrons

D. Isotopes1. All atoms of an element must have the same #

of protons, but they can have a different #of neutrons.

2. An atom with more or less neutrons than protons is called an isotope.

3. Some isotopes are radioactive- meaning the nucleus decays or breaks down over timea. Radioactive isotopes are used in research and

medicineb. We can track how an element moves through the body

if it is radioactive.c. Radioactive isotopes are also used in carbon dating to

determine the age of fossils and rocks found on earth.

4. Example: Carbon- 12 Carbon- 13 Carbon- 14 6 protons 6 protons 6 proton 6 neutrons 7 neutrons 8 neutrons 6 electrons 6 electrons 6 electrons

E. Ionic Bonds1. Forms when an

atom transfers an electron to another atom

2. Example: NaCl 3. Ions are formed as

a result of an ionic bonda. An ion is an atom

that has a chargeCation = + chargeAnion = - charge

F. Covalent bonds1. Forms when 2

atoms share electrons

2. Example: H2O

G. Chemical Reactions1. Occur when existing chemical bonds are broken

and new ones are created to form a new substance

2. Some reactions release energy and some absorb energy

3. Reactants are on the left side of the arrow, products are on the right side of the arrow

4. Do not create or destroy matter, only rearrange

Warm-up 9/4/131. Why do all isotopes of an element have the

same chemical properties?- b/c they all have the same # of protons and electrons

2. Water (H2O) and hydrogen peroxide (H2O2) both consist of H and O atoms. Explain why they have different physical and chemical properties.- the 2 compounds have different properties b/c they contain different proportions of H and O atoms

3. How many mL are in 4 gallons? - 4 gal x 3.785 L x 1000 mL = 15,140 mL

1 gal 1 L

II. Properties of Water

A. The structure of H2O

1. 2 H atoms are joined to an O atom by a single covalent bond

2. H2O is a polar molecule, meaning the molecule has opposite ends with opposite chargesa. This happens when the O pulls the

electrons much more strongly than the H atom

3. H20 molecules are attracted to each other by a very weak bond called a hydrogen bond

B. Water’s Life Supporting Properties1. Cohesion & Adhesion

a. Cohesion: the tendency of molecules of the same kind to stick together (pg. 41 Fig 2-7)

b. Adhesion: the type of attraction that occurs between unlike molecules

c. Help transport water from roots up to the leaves in a tree

2. Heat Capacitya. due to H bonding, water has the

ability to resist temperature changeb. helps to keep our body temperature

stable3. Low Density of Ice

a. usually an element in the solid is more dense than the liquid state

b. water is the opposite: the solid form is less dense than the liquid form (remember…ice floats)

4. Water’s Ability to Dissolve Other Substancesa. solvent: the substance that does the

dissolving (WATER)b. solute: the substance being dissolved

(SALT)c. solution: the solute dissolved in the

solvent (SALT WATER)d. aqueous solution has water as the

solvente. water is the main solvent in the body

C. Acids, Bases and pH1. The pH scale

a. describes how acidic or basic a substance isb. scale is from 0-14. 0 being very acidic, 14 being

very basicc. Each pH unit represents a tenfold change in the

concentration of H+ ionsd. Pure water and substances that have an equal

amount of H+ and OH- ions are said to the neutral with a pH of 7.

e. Substances with a low pH have lots of H+ ions and are considered to be acidic.

f. Substances with a high pH have lots of OH- ions and are considered to be basic.

H+ = hydrogen ion OH- = hydroxide ion