Petroleum and Hydrocarbon Behaviors Chapter 3, Section A Petroleum and Hydrocarbon Behaviors

What is petroleum!? Petroleum from the ground is also known as crude oil varies in color or texture cannot be used in its natural state Refined petroleum is a mixture of various hydrocarbons. Hydrocarbons – molecular compounds that contain atoms of the elements hydrogen and carbon.

Uses Petroleum can be used in: Fuel C.D.’s Sports Equipment Clothing Automobile Parts Carpeting Prescription drugs Artificial limbs And many more!!!

To Build or Burn? 89% of petroleum is burned outright as fuel 7% is used for producing substances such as medications and plastics 4% is used as lubricants, road paving materials, and an assortment of other products

C8H18 (l) + O2 (g) → CO2 (g)+ H2O(g) Where do they go??!? When molecules in petroleum are burned or used for manufacturing, they change forms. When hydrocarbons burn, they react with oxygen gas to form carbon dioxide gas and water vapor: C8H18 (l) + O2 (g) → CO2 (g)+ H2O(g)

Is petroleum renewable? NO! Petroleum is considered a nonrenewable resource. It takes millions of years to replenish. It is formed when plants and animals decay under layers of sand and mud for millions of years.

Where is the world’s oil?

3A.3 Petroleum Refining Crude oil is a mixture of many compounds Separating it into useful parts requires distillation The refining process does not separate each compound in the crude oil. It separates then into groups with similar boiling points called fractions. The distillation process is therefore called fractional distillation.

3A.3 Petroleum Refining Fractional distillation – separating a mixture into its components by boiling and condensing the components sequentially

3A.3 Petroleum Refining Fractional Distillation Process: The crude oil is heated at the bottom. Components with lower boiling points boil/evaporate first and rise up the column. The higher the gases go, the cooler the tower gets. When the vapors hit the right temperature, they condense back to a liquid on condenser trays. Since the column is coolest at the top, low b.p. molecules condense at the top while high b.p. molecules stay toward the bottom.

3A.4 A Look at Petroleum’s Molecules Intermolecular Forces - forces of attraction between molecules Gaseous hydrocarbons (1 to 4 carbons) have the weakest intermolecular forces. Low Viscosity (flows freely) Low Boiling Point Liquid hydrocarbon fractions (5 to 20 carbons) have stronger intermolecular forces. Solid hydrocarbons (20+ carbons) have the strongest intermolecular forces and highest boiling points.

3A.4 A Look at Petroleum’s Molecules More carbons generally mean intermolecular forces and boiling points! STRONGER HIGHER

3A.6 Chemical Bonding Nucleus contains protons and neutrons Nucleus: Central region containing the protons and neutrons. Energy level (or Shell): Space surrounding the nucleus containing the electrons. Nucleus contains protons and neutrons Shells describe general energy and location of electrons

3A.6 Chemical Bonding The period an element is in tells you how many energy levels are in the atom. 7 periods means 7 shells or energy levels Potassium has 4 energy levels. How many are in carbon? 2 How many levels are in aluminum? 3

3A.6 Chemical Bonding The highest energy level is the most important for an atom. The 1st energy level can only hold 2 electrons. The highest energy level can only hold 8 electrons. Octet Rule: an atom will share or transfer electrons in order to have a full energy level.

3A.6 Chemical Bonding The number of electrons in the highest energy level of an atom are called the valence electrons. Group 1: 1 valence electron Group 2: 2 valence electrons Groups 13-18: Group # - 10 Ex: Sodium, Na, is in group 1 so it has 1 valence electron. How many valence electrons does carbon have? 4 How many valence electrons does neon have? 8 How many valence electrons does chlorine have? 7

3A.6 Chemical Bonding Ne N C Be Electron Dot Notation Shows the symbol with the number of valence electrons around element. Space out electrons one at a time with no more than 2 to a side Ne N C Be

Electron Dot Diagrams H Ne Ar Kr He Li Be B C N O F Cl Br Na Mg Al Si Group 1A 2A 3A 4A 5A 6A 7A 8A 1 2 13 14 15 16 17 18 H Ne Ar Kr He Li Be B C N O F Cl Br Na Mg Al Si P S In an electron dot diagram, each dot represents a valence electron. K Ca Ga Ge As Se s1 s2 s2p1 s2p2 s2p3 s2p4 s2p5 s2p6 = valence electron

3A.6 Chemical Bonding Elements with a full outer energy level (usually 8 electrons) are very stable. What group of elements have a full outer level? Noble gases Why are they called noble? They are stable enough that they don’t react with the other elements to become stable.

3A.6 Chemical Bonding Other elements will gain or lose electrons (making ions in ionic compounds) or share electrons (molecules) to get a full octet like a noble gas. Why is the formula of hydrogen gas H2?

3A.6 Chemical Bonding H + H  H H Electron Dot Diagrams shows us the answer! If they share H H H Neither full Both full Draw the dot structure of 2 hydrogen atoms: H + H  H H

3A.6 Chemical Bonding Covalent bond – sharing of electrons to become stable. Single covalent bond – sharing 1 pair of electrons.

F F Sharing Electrons 8 Valence electrons 8 Valence electrons Fluorine has seven valence electrons A second F atom also has seven By sharing electrons Both end with full orbitals (stable octets) 8 Valence electrons 8 Valence electrons F F 26

3A.6 Chemical Bonding Nonmetals (right of stairs) form covalent bonds when they combine to make a molecule. Hydrocarbons (both nonmetals) are therefore held together by covalent bonds. By looking at the electrons, you can see why the simplest hydrocarbon, methane, has a formula of CH4.

The carbon has 8 electrons and each hydrogen has 2, making it stable. 3A.6 Chemical Bonding H H C H 4H + C  Electron-dot formula The carbon has 8 electrons and each hydrogen has 2, making it stable.

3A.6 Chemical Bonding H H C H Structural formula –the bonds are shown by a dash When there are many electrons, this makes the structure less confusing. H H C H

Alkanes Definition: hydrocarbon that contains single bonds only Naming: 1 C methane 6 C hexane 2 C ethane 7 C heptane 3 C propane 8 C octane 4 C butane 9 C nonane 5 C pentane 10 C decane What is the name of this alkane? BUTANE!

Alkanes Alkanes are all saturated hydrocarbons Defn: each carbon bonded to the maximum of 4 other atoms. Finding Formulas of Alkanes: CnH2n+2 Example: What is the name and formula of an alkane with 3 carbons? C3H8, Propane

Isomers Definition: molecules with the same chemical formula but different structural formulas Alkanes with 4 or more carbons all have isomers. H