Notes 7 – Compound Structure & Organic Compounds

The Structure of Compounds Substances that are compounds contain two or more types of atoms chemically bonded together Substances that are compounds contain two or more types of atoms chemically bonded together Chemical bonds are the difference between a mixture and a compound Chemical bonds are the difference between a mixture and a compound The structure of a substance is created by the bonding between atoms The structure of a substance is created by the bonding between atoms There are 2 main types of compound structure: There are 2 main types of compound structure: 1.Network Structure 2.Molecular Structure

What are network structures? Network structures –compounds where every particle is bonded to other particles throughout the whole substance Network structures –compounds where every particle is bonded to other particles throughout the whole substance Can be formed by the sharing of electrons OR the transfer of electrons between atoms Can be formed by the sharing of electrons OR the transfer of electrons between atoms Some substances are networks of ions held together by ionic bonds (ionic networks) Some substances are networks of ions held together by ionic bonds (ionic networks) Ex. Salt (NaCl) Ex. Salt (NaCl) Some substances are networks of molecules held together by covalent bonds (covalent networks) Some substances are networks of molecules held together by covalent bonds (covalent networks) Ex. Quartz (SiO 2 ) Ex. Quartz (SiO 2 )

Properties of Network Structures Extremely strong structures Extremely strong structures High melting points High melting points NaCl melts at 801 °C NaCl melts at 801 °C SiO 2 melts at 1700 °C SiO 2 melts at 1700 °C Solids at room temperature Solids at room temperature Can be dissolved in water Can be dissolved in water Covalently bonded network structures are extremely hard Covalently bonded network structures are extremely hard Ex. Diamond Ex. Diamond

What are molecular structures? Molecular structures – compounds made of covalently bonded molecules that are weakly attracted to one another Molecular structures – compounds made of covalently bonded molecules that are weakly attracted to one another Ex. Water (H 2 O), Glucose (C 6 H 12 O 6 ) Ex. Water (H 2 O), Glucose (C 6 H 12 O 6 ) Can only be formed by the sharing of electrons between atoms Can only be formed by the sharing of electrons between atoms Individual molecules in the substance are attracted to each other but not strongly connected Individual molecules in the substance are attracted to each other but not strongly connected

Properties of Molecular Structures Not very strong structures Not very strong structures Low melting points Low melting points H 2 O melts at 0 °C H 2 O melts at 0 °C CO 2 melts at -78 °C CO 2 melts at -78 °C Sucrose (sugar), C 12 H 22 O 11 melts at 185 °C Sucrose (sugar), C 12 H 22 O 11 melts at 185 °C Usually liquids or gases at room temperature Usually liquids or gases at room temperature Ex. water, vegetable oil, carbon dioxide, methane Ex. water, vegetable oil, carbon dioxide, methane Sometimes solids at room temperature Sometimes solids at room temperature Ex. sugar, plastic, wax, fats Ex. sugar, plastic, wax, fats

What are organic compounds? Organic compound – a covalently bonded compound made of molecules that contain carbon Organic compound – a covalently bonded compound made of molecules that contain carbon Always have a molecular structure Always have a molecular structure Usually contain hydrogen as well as carbon Usually contain hydrogen as well as carbon May contain other non-metals such as oxygen, nitrogen, sulfur, or phosphorous May contain other non-metals such as oxygen, nitrogen, sulfur, or phosphorous Come from living organisms and the remains of dead organisms Come from living organisms and the remains of dead organisms Ex. sugar, cellulose, insulin, protein, DNA, coal, petroleum Ex. sugar, cellulose, insulin, protein, DNA, coal, petroleum

The Versatility of Carbon Atoms Carbon atoms have a valence of 4 Carbon atoms have a valence of 4 In order to become stable, carbon atoms can form up to 4 covalent bonds In order to become stable, carbon atoms can form up to 4 covalent bonds One carbon atom might form: One carbon atom might form: 4 single covalent bonds 4 single covalent bonds 2 single and 1 double covalent bond 2 single and 1 double covalent bond 2 double covalent bonds 2 double covalent bonds 1 triple and 1 single covalent bond 1 triple and 1 single covalent bond Carbon atoms can form an large variety of molecules (chains, rings, branched chains) Carbon atoms can form an large variety of molecules (chains, rings, branched chains)

What are hydrocarbons? Hydrocarbon – an organic compound made of carbon and hydrogen Hydrocarbon – an organic compound made of carbon and hydrogen Two common types of hydrocarbons are alkanes and alkenes Two common types of hydrocarbons are alkanes and alkenes Alkanes – hydrocarbons with only single covalent bonds Alkanes – hydrocarbons with only single covalent bonds Alkenes – hydrocarbons with at least one double covalent bond Alkenes – hydrocarbons with at least one double covalent bond

Naming Hydrocarbons The prefix indicates the number of carbon atoms in the molecule The prefix indicates the number of carbon atoms in the molecule The suffix indicates the type of bonds between the carbon atoms The suffix indicates the type of bonds between the carbon atoms ane = single bonds ane = single bonds ene = at least one double bond ene = at least one double bond Ex. pentane Ex. pentane A 5 carbon molecule (pent) with all single bonds (ane) A 5 carbon molecule (pent) with all single bonds (ane) Ex. Propene Ex. Propene A 3 carbon molecule (prop) with one double bond (ene) A 3 carbon molecule (prop) with one double bond (ene) meth= 1 eth= 2 prop= 3 but= 4 pent= 5 hex= 6 hept= 7 oct= 8 non= 9 dec= 10 Hydrocarbon Prefixes

Methane CH 4

Ethane C 2 H 6

Propane C 3 H 8

Ethene C 2 H 4

Propene C 3 H 6

Samples What would be the name of a hydrocarbon with 8 carbon atoms and one double bond? What would be the name of a hydrocarbon with 8 carbon atoms and one double bond? 8 = oct 8 = oct double bond = ene double bond = ene octene octene Describe the structure of nonane Describe the structure of nonane non = 9 non = 9 ane = single bonds ane = single bonds A 9 carbon hydrocarbon with all single bonds A 9 carbon hydrocarbon with all single bonds

What are alcohols? Alcohol – an organic compound that is made of carbon, hydrogen, and an oxygen atom Alcohol – an organic compound that is made of carbon, hydrogen, and an oxygen atom Alcohols have “OH” groups (an oxygen bonded to a hydrogen) Alcohols have “OH” groups (an oxygen bonded to a hydrogen) Alcohols are named just like alkanes and alkenes, but with “ol” at the end Alcohols are named just like alkanes and alkenes, but with “ol” at the end Ex. ethanol Ex. ethanol Ethanol has two carbons (eth), single bonds (an), and an –OH group (ol) Ethanol has two carbons (eth), single bonds (an), and an –OH group (ol)

Methanol CH 3 OH

Ethanol C 2 H 5 OH

Ethenol C 2 H 3 OH

What are isomers? Isomers – compounds that have the same chemical formula, but different structures Isomers – compounds that have the same chemical formula, but different structures Ex. pentane and 2 methyl-butane Ex. pentane and 2 methyl-butane Both have formula C 5 H 12 Both have formula C 5 H 12 Pentane - straight chain of 5 carbons Pentane - straight chain of 5 carbons 2 methyl-butane - chain of 4 carbons with a 1 carbon branch 2 methyl-butane - chain of 4 carbons with a 1 carbon branch