Chemistry 20 Review Electrons, Protons, Neutrons Atomic/Molar Mass Lewis Diagrams & Structural Formulas Number of Bonding Electrons Intermolecular Forces Hydrocarbons and Melting/Boiling Point
Number of Protons is ALWAYS equal to the Atomic Number…..the number found on the periodic table. Number of Electrons is equal to Protons ONLY IN NEUTRAL ATOMS! In (Non-Un-Dis?)…..compounds/ions that are not neutral you have to look at the Overall Charge to determine how many electrons. Overall Charge is the Protons (+) + Electrons (-). Neutrons are usually equal to the number of protons….. ***You need to know the Atomic/Molar mass to know for sure.*** Chemistry 20 ReviewElectrons, Protons, Neutrons…
Atomic mass is the combined weight of Protons, Neutrons, and Electrons. Protons and Neutrons have the most weight….that extra little bit….usually a few decimals is the weight of the electrons…..they have a very small weight. Atomic Mass….. H 1.01g/mol C 12.01g/mol Cl35.45g/mol Atomic mass is equal to [#P + #N]….the extra little bit is the weight of the electrons. Chemistry 20 ReviewAtomic/Molar Mass
How do you calculate the atomic/molar mass of a compound? H2O? 2 X H = 2.02g/mol 1 X O = 16.00g/mol Total = 18.02g/mol C6H12O6? 6 X C = 72.00g/mol 12 X H = 12.12g/mol 6 X O = 96.00g/mol Total = 180.12g/mol Chemistry 20 ReviewAtomic/Molar Mass
Also known as Lewis Dot Diagrams. Diagrams where you put the symbol of the element in the center and draw the Valence electrons around it represented by dots. DONE Chemistry 20 ReviewLewis Diagrams Oxygen is in group VI A (group 16)…….so it has 6 valence electrons. So start at the top and go clock wise until you have put 6 “dots” around the O.
When we draw the Lewis Dot Diagram for oxygen we notice that there are 2 pairs. And 2 single electrons. Single electrons are electrons that can form bonds. Singles electrons are called bonding electrons. So, how many bonds can oxygen form? 2 Chemistry 20 ReviewBonding Electrons
Structural diagrams look very similar to Lewis diagrams. But they do not show electrons, they only show bonds in a compound OR polyatomic atom…H2 Cl2, F2, I2 S8 P4 H C CH4 H H H If we draw a Carbon Lewis Dot Diagram OR look to see its in group 14 which means it has 4 bonding electrons. Well carbon can form 4 bonds and there’s 4 hydrogen’s, so put one on each side and connect them with a line to show a bond. Chemistry 20 ReviewStructural Diagrams/Formulae
3 Types of Intermolecular forces: • Dipole-Dipole Forces • Using electronegativity to assign dipoles • Polar and Non-Polar Molecules • London Dispersion • Momentary Dipole-Dipole attraction. • Random chance of electrons of a bond being unequally shared. • Hydrogen Bonding • Hydrogen bonded to another atom other than hydrogen. • H-O H-Cl H-F H-N Chemistry 20 ReviewIntermolecular Forces
A general rule to follow is that the greater the number of C’s and H’s a compounds has the higher its melting and boiling points. Chemistry 20 ReviewHydrocarbon Melting/Boiling Points
Hydrocarbons are compounds containing Hydrogen and Carbon (Often referred to as fossil fuels). CH4 C2H6 C3H8
What Kind of Chemical Potential Energy Do We Use…Have A Lot of In Alberta? Where did the energy in things like Oil and Gas come from….originally?
From The Sun To Your Gas Tank Dead Plant Photosynthesis Covered By Sediment Millions of Years Pass By Fossil Fuel
Fossil fuels are the main source of hydrocarbons. There are many forms of fossil fuels such as:
Comes from living sources, things that are now or were once alive. • Synthesized compounds. • Often called Natural compounds because they can be found in nature. • Not natural, can be found, but not a large part of living things. • Source of fossil fuels. • Usually Ionic Compounds. • Main source of hydrocarbons. • CO3 CN- Na2CO3 NaCl CaC2 Organic & Inorganic • “CHON” • ….Not CHON….. • Carbon, Hydrogen, Oxygen, Nitrogen. • Opposite or organic….. Its spelt different……It has “In” in front...
Most fossil fuels in their raw/natural form cannot be used by humans. In order to make fossil fuels into a form that can be used by humans they need to be refined. Refining Fossil Fuels
Raw natural gas is actually a mixture of different hydrocarbons and poisonous Hydrogen Sulfide (H2S(g)) and needs to be refined before it can be used. The first process that has to happen to raw natural gas is the removal of the poisonous component through a process called “sweetening”. The removed Poisonous Hydrogen Sulfide (H2S(g)) and SO2(g) are then further reacted in a “Clause Converter” and are tuned into solid sulfur. But even after the removal of the Hydrogen Sulfide (H2S(g)) the raw natural gas still contains a number of other hydrocarbons and must be further refined before it can be used.
Raw Natural Gas ***In general any hydrocarbon longer than 4 carbons is liquid at room temperature.
1. you have to count the number of carbons in the hydrocarbon chain and use the prefix . Naming Hydrocarbon “Chains”
2. you have to determine is the hydrocarbon is saturated or unsaturated. Saturated Hydrocarbons: Saturated Hydrocarbons are hydrogen and carbon containing compounds that contain ONLY single bonds between carbons. Maximum number of hydrogens. Naming Hydrocarbon “Chains” Unsaturated Hydrocarbons: Unsaturated hydrocarbons are compounds that contain double or triple bonds between carbons.
Alkanes, Alkenes, and Alkynes Saturated SINGLE BONDS Unsaturated DOUBLE BONDS Unsaturated TRIPLE BONDS Naming Hydrocarbon “Chains”
1. Count the number of carbons in the chain. 2. Saturated (ONLY SINGLE BONDS) or Unsaturated (DOUBLE –ene or Triple-Yne) 3 4 2 1 Structural Formula Hydrocarbon Name: But ane Practice:
1. Count the number of carbons in the chain. 2. Saturated (ONLY SINGLE BONDS) or Unsaturated (DOUBLE –ene or Triple-Yne) Structural Formula Hydrocarbon Name: Pent ane Practice:
Structural Formula Hydrocarbon Name: Decane Practice:
Not all hydrocarbons are straight chains, often they have side branches like a tree. Branched Alkanes Branched alkanes get named the same way as far as the long Parent chain is concerned. You still look for the longest number of carbons in a row.
1. Count the number of carbons in the chain. Saturated (ONLY SINGLE BONDS) or Unsaturated (DOUBLE –ene or Triple-Yne) 2. ***To name the side branch, you need to indicate which carbon it is connected to.*** Branched Alkanes ane But
So we have to number the longest chain so we can say where the “branch” is connected. 4 3 1 2 1 3 2 4 ***The rule is you number the carbons so that the branch is on the lowest number*** Or So… Branched Alkanes ane But
So lets look just at the branch. 4 3 1 2 So just like with the parent chain, how many carbons long is the branch? ***All side branches end in –yl*** 1 Carbon Prefix for 1 carbon? Branched Alkanes ane But Meth yl Meth
Last thing. What number carbon is the Methyl branch connected to? 4 3 1 2 Branched Alkanes ane But 2- Meth yl
1. 2. 3. Number the carbons so the chain is on lowest carbon number. 5 2 4 1 3 4. Name the branch. Practice(easy) 5. What carbon is the branch on? 3- Ethyl Pentane
1. Ethyl 2. 3. Number the carbons so the chain is on lowest carbon number. 5 4 3 2 1 Methyl Methyl 4. Name the branches. Alphabetically… Di Practice(Advanced) 5. What carbon is the branch on? Pentane 3- Ethyl -2,4- Dimethyl
Cycloalkanes are hydrocarbons that are bound together in a ring. Name them the same as a straight branch, just write “Cyclo” in front.
1. 2. Cyclo hexane
1. 2. 3. Number the carbons so the chain is on lowest carbon number…..Clockwise-Counter clockwise, whatever. Di Methyl 2 Methyl 4. 3 1 Name the branch. 5. 5 4 What carbon is the branch on? pentane 1,2- dimethyl cyclo
Challenging 1. Di Methyl 2. Methyl 2 3. Number the carbons so the chain is on lowest carbon number. 3 1 4. 4 5 Name the branch. **** Have to start numbering at double bond…it has priority*** 5. What carbon is the branch on? dimethyl Cyclo pent 2,3-
Challenging Di Are we done? What carbon is the double bond on? If we always number starting at the double bond…do we need to say 1? Methyl Methyl 2 3 1 4 5 dimethyl Cyclo pent 2,3- ene
Saturated: Contains as many Hydrogens as possible. Unsaturated: Do not contain as many Hydrogens as possible.
Hydrogenation: The process of adding H2(g) to an UNSATURATED hydrocarbon causing it to become more saturated.
The naming system for Alkenes and Alkynes is the same as for Alkenes. 1. Count the number of carbons in the chain. 3. Number the carbons so the chain is on lowest carbon number. 2. 4. Saturated (ONLY SINGLE BONDS) or Unsaturated (DOUBLE –ene or Triple-Yne) Name the branch. 5. What carbon is the branch on?
1 2 3 4 2- methyl ene But 4,4 – dimethyl hept-2-yne 4,4 – dimethyl pentene
5-ethyl-4-methylhept-2-yne ***you have to number the chain so that the “yne” as the lowest number***
Hydrocarbon cracking is the process of breaking large(single bonded….saturated) hydrocarbons into smaller (often unsaturated) hydrocarbons. Hydrocarbon cracking is done HIGH TEMPERATURESWITH OR WITHOUT a catalyst. H H H H H H C-C-C-C- H H H H H H H H H H H H H H + Heat C-C-C-C-C-C-C-C H H H H H H H H H H H H H H C-C-C-C- H H H H
Ethane cracking is the a special hydrocarbon cracking in which Ethane (single bonded-Saturated) is “cracked” into Ethyne (double bonded-unsaturated).