152x Filetype PPTX File size 0.40 MB Source: chemhesstry.weebly.com
• A.3 Petroleum Refining • Crude oil is a mixture of many components, refining does not separate each compound • Refining produces several distinct mixtures • Fractions • Distinctive mixtures produced by large scale refining • Range of properties in each mixture • Fractions will have distinct uses • Fractional distillation • Process of refining crude oil • Very tall columns • Vaporized molecules continue upwards in column • The higher it gets, more molecules condense as the temperature cools • At the top, only the very lightest molecules remain a vapor • Heavy molecules stay at the bottom of the column, as temperatures cannot get high enough to boil. They are called bottoms • A.4 Examining Petroleum’s molecules • Intermolecular forces • Forces of attraction between molecules • Gases have very weak intermolecular forces • Weak forces allow molecules to readily separate from each other • Gas fractions contain compounds with low boiling points (<40C) • 1-4 carbons • only slight molecular attractions • Found at the top of column • •
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