Crude oil and hydrocarbons

• What is crude oil primarily composed of?


  Crude oil is primarily composed of **hydrocarbons**, which are compounds made up of hydrogen and carbon atoms.
• What is the general formula for alkanes?

  The general formula for alkanes is $C_nH_{2n+2}$, where *n* is the number of carbon atoms.
• What is the general formula for alkenes?

  The general formula for alkenes is $C_nH_{2n}$, where *n* is the number of carbon atoms.
• What is the key difference between alkanes and alkenes?

  Alkanes are **saturated hydrocarbons** with single bonds only, while alkenes are **unsaturated hydrocarbons** with at least one double bond.
• What is a common use of alkenes?

  Alkenes are used in the production of **plastics** (e.g., polyethylene) and **chemical synthesis**.
• What is the test for alkenes?

  Alkenes turn **bromine water from orange to colorless** due to the addition reaction with the double bond.
• What is fractional distillation?

  A process used to separate a mixture of liquids with different boiling points by heating and condensing them at different temperatures.
• What is the purpose of a fractionating column in fractional distillation?

  To provide multiple surfaces for vapor to condense and re-evaporate, improving the separation of components based on their boiling points.
• What is the key principle behind fractional distillation?

  Different liquids have different boiling points, allowing them to be separated by heating the mixture and collecting the vapors at specific temperatures.
• What is an example of a mixture separated by fractional distillation?

  Crude oil is separated into fractions like gasoline, diesel, and kerosene using fractional distillation.
• What happens to the liquid with the lowest boiling point during fractional distillation?

  It vaporizes first and is collected at the top of the fractionating column.
• What is the role of temperature in fractional distillation?

  Temperature is carefully controlled to ensure that each component vaporizes and condenses at its specific boiling point.