Topics for Today What is in my gasoline? Burning a gallon of gasoline…

Readings for Today 3.6 Quantitative Concepts: Mass 3.7 Quantitative Concepts: Molecules and Moles

Topics for Wednesday Burning a gallon of gasoline. Where does my gasoline come from?

Readings for Wednesday 3.6 Quantitative Concepts: Mass 3.7 Quantitative Concepts: Molecules and Moles

Topics for Friday Exam #2

Topics for Monday Greenhouse Earth!

Topics for Today What is in my gasoline? Burning a gallon of gasoline…

What is in my gasoline?

Gasoline A volatile mixture of flammable liquid hydrocarbons derived chiefly from crude petroleum and used principally as a fuel for internal-combustion engines.

Gasoline A volatile mixture of flammable liquid hydrocarbons derived chiefly from crude petroleum and used principally as a fuel for internal-combustion engines. What is “volatile?”

N 2 + O 2 2NO NO + O 2 +. OH + VOCs NO 2 + VOCs high temp VOC = Volatile Organic Compounds Easily goes into the vapor phase Contains C

Some VOCs Methane (1 carbon) Ethane (2 carbons) Propane (3 carbons) Butane (4 carbons) Octane (8 carbons)

Gasoline A volatile mixture of flammable liquid hydrocarbons derived chiefly from crude petroleum and used principally as a fuel for internal-combustion engines. What is “volatile?” A barrel Liquid Vapor

Gasoline A volatile mixture of flammable liquid hydrocarbons derived chiefly from crude petroleum and used principally as a fuel for internal-combustion engines. What is a “mixture?”

Matter MixturesPure Substances Compounds Elements HeterogeneousHomogeneous Is gasoline heterogeneous or homogenous?

Gasoline A volatile mixture of flammable liquid hydrocarbons derived chiefly from crude petroleum and used principally as a fuel for internal-combustion engines. What is “flammable?”

Complete combustion of methane CH 4 + 2O 2  CO 2 + 2H 2 O Undergoes combustion !

Gasoline A volatile mixture of flammable liquid hydrocarbons derived chiefly from crude petroleum and used principally as a fuel for internal-combustion engines. What is a “hydrocarbon?”

Paraffin is a hydrocarbon -C -C-HH-C HHHHHHHHHHHHHHHHHHHHHH HHHHHHHHHHHHHHHHHHHHHH

Gasoline A volatile mixture of flammable liquid hydrocarbons derived chiefly from crude petroleum and used principally as a fuel for internal-combustion engines. What is a “hydrocarbon?” A molecule that contains ONLY carbon and hydrogen atoms.

Some hydrocarbons Methane Ethane Propane Butane Octane

Some hydrocarbons Methane Ethane Propane Butane Octane

Gasoline A volatile mixture of flammable liquid hydrocarbons derived chiefly from crude petroleum and used principally as a fuel for internal-combustion engines. Gasoline is a mixture (homogeneous) of over 300 different compounds!!

What’s in my gasoline? n-alkanes (straight chain) iso-alkanes (branched) Cycloalkanes Alkenes and Alkynes Aromatics 15-25% 20-30% <1%

What’s in my gasoline? n-alkanes (straight chain) iso-alkanes (branched) Cycloalkanes Alkenes and Alkynes Aromatics 15-25% 20-30% <1%

n-alkanes in gasoline n-pentane (5 carbons) n-hexane (6 carbons) n-heptane (7 carbons) n-octane (8 carbons) etc… The n stands for “normal,” or straight chain.

n-butane C C H H H n-butane, C 4 H 10 H H C H H C H H H

n-butane C C H H H n-butane, C 4 H 10 H H C H H C H H H OR

CH 3 -CH 2 -CH 2 -CH 3 n-butane, C 4 H 10 Condensed structural formula!

n-butane Figure 10.3 page 436

n-pentane C C H H H n-pentane, C 5 H 12 H H C H H C H H C H H H Be able to draw and name these structures from methane to octane!

What’s in my gasoline? n-alkanes (straight chain) iso-alkanes (branched) Cycloalkanes Alkenes and Alkynes Aromatics 15-25% 20-30% <1%

Compare CH 3 -CH 2 -CH 2 -CH 3 n-butane, C 4 H 10

Compare C C H H H n-butane, C 4 H 10 H H C H H C H H H

isobutane C C H H H isobutane, C 4 H 10 H C C H H H H HH Structural Formula

CH 3 -CH-CH 3 isobutane, C 4 H 10 Condensed structural formula! CH 3

n-butane Figure 10.3 page 436

iso-butane Figure 10.3 page 436

n-butane and isobutane are isomers! Isomer = Same chemical formula but different chemical structure!!!

isobutane C C H H H isobutane, C 4 H 10 H C C H H H H HH Also known as

isobutane C C H H H isobutane, C 4 H 10 H C C H H H H HH Also known as 2-methylpropane

isobutane C C H H H isobutane, C 4 H 10 H C C H H H H HH Also known as 2-methylpropane 1 23

isobutane C C H H H isobutane, C 4 H 10 H C C H H H H HH Also known as 2-methylpropane 1 23 methyl,. CH 3

Some VOCs Methane (1 carbon) Ethane (2 carbons) Propane (3 carbons) Butane (4 carbons) Octane ( 8 carbons)

Methyl (1 carbon). CH 3 Ethyl (2 carbons) Propyl (3 carbons)

n-octane CH 3 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 3 Chemical formula? C 8 H 18 Not too much of this in gasoline…

isooctane Chemical formula? C 8 H 18 CH 3 -C-CH 2 -CH-CH 3 CH 3 Isomers!!

Chemical formula? CH 3 CHCH 2 CH 3 2-methylpentane

Chemical formula? C 6 H 14 CH 3 CHCH 2 CH 3 2-methylpentane

CH 3 CHCH 2 CH 3 CHCH 2 CH 3 Same or different? =? 2-methylpentane

CH 3 CHCH 2 CH 3 CHCH 2 CH 3 Same or different? = 2-methylpentane

CH 3 CHCH 2 CH 3 CH 2 CHCH 3 =? Same or different?

2-methylpentane CH 3 CHCH 2 CH 3 CH 2 CHCH 3 = Same or different?

What’s in my gasoline? n-alkanes (straight chain) iso-alkanes (branched) Cycloalkanes Alkenes and Alkynes Aromatics 15-25% 20-30% <1%

cycloalkanes cyclopentane methylcyclopentane cyclohexane methylcyclohexane etc…

Basically geometrical figures…

cyclopentane CH 2 H2CH2C H2CH2C Chemical formula? C 5 H 10

cyclopentane CH 2 H2CH2C H2CH2C Chemical formula? C 5 H 10 Isomer of n-pentane?

NO!! Different chemical formulas. CH 2 H2CH2C H2CH2C C C H H H Pentane, C 5 H 12 H H C H H C H H C H H H Cyclopentane, C 5 H 10

cyclohexane H2CH2C H2CH2C H2CH2CCH 2 Chemical formula? C 6 H 12 Isomer of n-hexane? NO! I will leave you to prove this to yourself

cyclohexane C C C C C C H H H H H H H H H H H H

methylcyclohexane C C C C C C CH 3 H H H H H H H H H H H

What’s in my gasoline? n-alkanes (straight chain) iso-alkanes (branched) Cycloalkanes Alkenes and Alkynes Aromatics 15-25% 20-30% <1%

Alkenes Hydrocarbons with a C-C double bond.

Alkenes ethene (or ethylene) propene etc…

Ethene 1) Draw carbon atoms

Ethene CC 2) Fill in C-C bonds

Ethene CC 3) Fill in hydrogen atoms HH H H C2H4C2H4 Notice the shape!!

2-pentene CH CH 3 CH 2 CH C 5 H 10

1-pentene CHCH 2 CH C 5 H 10

1-pentene C 5 H 10 CH 2 = CH – CH 2 – CH 2 – CH 3 H 2 C = CH – CH 2 – CH 2 – CH 3 C = C CH 2 – CH 2 – CH 3 H H H

CH CH 3 CH 2 CH CHCH 2 CH Are 1-pentene and 2-pentene isomers?

What’s in my gasoline? n-alkanes (straight chain) iso-alkanes (branched) Cycloalkanes Alkenes and Alkynes Aromatics 15-25% 20-30% <1%

Aromatics Contain 1 or more benzene rings.

Figure 10.4 p. 438 Fig.10.04a

Figure 10.4 p. 438

Figure 10.4 p. 438 Fig.10.04d

Figure 10.4 p. 438

Because of its toxicity, gasoline only contains TRACE amounts of benzene. Then, what aromatics are in gasoline?

Toluene, C 7 H 8 H HCH 3 H H H C C C C C C Benzene, with a methyl group attached

Toluene CH 3 Also called methylbenzene!!!

CH 3 Isomers? C7H8C7H8 C7H8C7H8 NO!! They are the SAME MOLECULE

Isomer = Same chemical formula but different chemical structure!!!

Xylenes CH 3 Benzene with TWO methyl groups attached.

CH 3 H3CH3C Isomers ? NO!! Same molecule Xylenes

CH 3 H3CH3C Isomers ? YES Xylenes

CH 3 H3CH3C Isomers ? YES Xylenes

Last but not least…

CH 2 CH 3 Benzene with an ethyl group attached. What is this called?

CH 2 CH 3 Benzene with an ethyl group attached. What is this called? Ethylbenzene, C 8 H 10