Exam 2

Organic Chemistry

the study of the chemistry of the carbon atom

Inorganic Chemistry

the study of the chemistry of the other elements

Biochemistry

the study of the chemical processes that take place in living organisms

Theory of Vital Force

a disproven theory that organic compounds can only be synthesized

Who disproved the “theory of vital force”?

Fredrich Wohler

What is the major element in biochemical compounds?

Carbon

____% of known chemical compounds are organic

85

Organic Compounds:

• Low melting point

• water insoluble

• soluble in organic solvents

• aqueous solutions don’t conduct electricity

• burn and decomposes (most)

• reactions are slow

Inorganic Compounds:

• ionic bonds

• high melting point

• water soluble

• insoluble in organic solvents

• aqueous solution conduct electricity

• very few burn

• reactions are fast

Common elements in organic compounds:

• hydrogen

• halogens

• oxygen

• sulfur

• nitrogen

• carbon

• phosphorus

Covalent bonds

formed by sharing of electrons

Functional Group

is an atom or group of atoms within a molecule that shows a characteristic set of physical and chemical properties

Organic compounds contain _____

covalent bonds

Polar covalent bonds

the unequal sharing of electrons when elements with different electronegativities form covalent bonds

Common molecular shapes

• tetrahedral

• pyramial

• bent

• trigonal planar

• linear

Bond angles

• 109.5 degrees

• 120 degrees

• 180 degrees

Polar molecule

molecule in which one side has a partial positive charge and the other has a partial negative charge

A polar molecule must…

contain one or more polar covalent bonds

Some molecules with polar covalent bonds are

nonpolar

Hydrogen bonds

Interaction of a nitrogen, oxygen, or fluorine atom with a hydrogen atom that has a covalent bond to a different nitrogen, oxygen, or fluorine atom. This causes the hydrogen to carry a partial positive charge.

Dipole-Dipole forces

a non-covalent attraction of neighboring polar groups for one another

London forces

a non-covalent interaction that involves the attraction of neighboring polar groups for one another

Hydrocarbon

organic compound that contains only H and C

Alkanes

no double or triple bonds (contains C-C bonds only)

Alkenes

contains one or more double bonds

Alkynes

contains one or more triple bonds

Arenes

a compound with one or more benzene rings

IUPAC

International Union of Pure and Applied Chemistry

IUPAC governs

nomenclature of chemical compounds

Alkyl groups

a group derived by removing a hydrogen from an alkane given the symbol R

Cycloalkanes

a hydrocarbon that contains carbon atoms joined to form a ring of carbons connected by single bonds

Polycyclic aromatic hydrocarbons

hydrocarbon containing benzene rings that are fused to one another

Constitutional Isomers

compounds with the same molecular formula, but a different order of attachment of their atoms

Conformation

the shapes that a molecule can take because of bond rotations

Conformations are…..

interconverted by rotation around a single bond

Geometric Isomers

stereoisomers that result from restricted bond rotation

Cycloalkanes and alkenes are molecules that can exist as….

Cis or Trans geometric isomers

Cis

same side

Trans

opposite side

Products containing alkanes

• natural gas

• petroleum

• liquified petroleum- propane

• gasoline

• diesel

• chlorofluorocarbons

Chlorofluorocarbons

hydrocarbons with halogens attached

Freon contains….

Fluorine

Chemical Reactions

a chemical change in which the covalent or ionic bonds that hold elements or compounds together are broken and new bonds are formed

Chemical Reactions are represented by…

chemical equations

Coefficients

numbers placed in front of the formula

NEVER CHANGE….

THE FORMULA

Types of reactions:

• synthesis

• decomposition

• single replacement

• double replacement

Reactions involving water

• hydrolysis

• hydration

• dehydration

Oxidation/Reduction

• combustion

• hydrogenation

Synthesis

two or more elements or compounds combined to form one or more complex compound

Decomposition

(reverse of synthesis) break down of one compound to form elements or simpler compounds

Single Replacement

one element trades places with a different element in a compound

Double Replacement

two elements trade places with each other

Hydrolysis

water (hydro) splits (lysis) another molecule

Catalyst

a substance that speeds up a reaction without itself being consumed or destroyed by the reaction

Hydration

addition of water across a double bond (alkene) in the presence of H+ (acid) catalyst

Oxidation/Reductions are often called

Redox reactions

Oxidation

loss of electrons

Reduction

gain of electrons

Combustion

special type of oxidation/reduction reaction involving oxygen

Organic Chemist identify

oxidation/reduction

Oxidation:

• lose of electrons

• increase attachment to oxygen

• decrease attachment to hydrogen

Reduction:

• gain of electrons

• decreased attachment to oxygen

• increase attachment to hydrogen

Many antiseptics are

oxidizing agents

Hydrogenation

addition of H2 across a double bond.Often requires a platinum (Pt) catalyst

Stoichiometry

the quantitative relationship between reactant and products in a chemical reaction

Chemical Reaction

rxn

If 6.0 mol CO is present, how many moles of O2 will be required to convert all of the CO to CO2?

2CO + O2 → 2CO2

3 molO2

If 6.0 mol CO is presnt, how many moles of CO2 will be produced if all of the CO is used up?

2CO + O2 → 2CO2

6 molCO2

Firefighters use a device called a “rebreather” to enter smoky buildings. Rebreathers use KO2 to remove carbon dioxide from air in the unit using the reaction below.

4KO2 + 2CO2 → 2K2CO3 + 3O2

How many grams of KO2 are required to completely react with 0.400 mol of CO2

56.88gKO2

Yield of Reaction

in the real world reactant are not always present in the exact ratio stated in the balanced chemical reaction

Limiting Reactant

is the reactant that determines (limits) the amount of product that can be formed in a rxn.

If 2.10 molN2 and 5.70 molH2 react, what is the limiting reagent?

N2 + 3H2 → 2NH3

H2 is the limiting reagent

Theoretical Yield

the maximum amount of product that can be obtained (controlled by amount of limiting reagent.)

If 2.2 molC3H8 (propane) reacts with 14 molO2 (oxygen), what is the theoretical yield?

C3H8 + 5O2 → 3CO2 + 4H2O

6.6 molCO2

Percent Yield

most real-world reactions do not produce the total theoretical yield, therefore we calculate percent yield to determine what the yield is

% yield = actual yield/theoretical * 100

Chemist classify reactions as:

Spontaneous

Nonspontaneous

Spontaneous

a reaction that continues by itself once it has started

Non-spontaneous

a reaction will not take place unless something starts it and keeps it going

Gibbs Free Energy (G) determines

if a reaction will take place (be spontaneous) or not take place (non-spontaneous)

Spontaneous reactions have…

Negative Delta G

Non-spontaneous reactions have a…

Positive Delta G

Reactions in equilibrium have…

Delta G=0

Reaction Rate

how quickly products form

Energy of activation

(Ea) the energy barrier that must be crossed to go from reactants to products

Determines Rate of Reaction

• the greater Ea the slower the rate

• Other factors that influence rate

  • temperature

  • concentration of reactant

  • presence of catalyst

Solids

matter with fixed volume and shape

Liquid

matter with a fixed volume, indefinite shape; takes on the shape of the container

Gases

matter with indefinite shape and volume; takes on both the shape and volume of its container

Melting

Solid → Liquid

Heat of fusion

amount of heat required to melt a solid

Freezing

Liquid → Solid

Evaporation

Liquid → Gas

Heat of vaporization

amount of heat required to evaporate a liquid

Deposition

Gas → Liquid

Sublimation

Solid → Gas

Atmospheric Pressure

pressure of column of air above and around the earth’s surface

STP

Standard Temperature and Pressure

Temp

0 degrees celsius