organic chem exam questions

Question 1

• Crude oil heated into fractional distillation column
• Column is hot at the bottom and cooler at the top
• Liquid (not evaporated) crude oil will stay at the
  bottom
• Gaseous crude oil will rise to the top
• Fractions will condense to liquid at their condensing
  point and separate out at different parts of the column
• Different fractions will have different length
  hydrocarbon chains OR different length hydrocarbons
  chains will condense at different points
• Different fractions will have different properties

Answer 1

• Crude oil heated into fractional distillation column
• Column is hot at the bottom and cooler at the top
• Liquid (not evaporated) crude oil will stay at the
  bottom
• Gaseous crude oil will rise to the top
• Fractions will condense to liquid at their condensing
  point and separate out at different parts of the column
• Different fractions will have different length
  hydrocarbon chains OR different length hydrocarbons
  chains will condense at different points
• Different fractions will have different properties

Question 2

Explain the need for cracking

Answer 2

• More long hydrocarbons are produced than needed
• High demand for short chain hydrocarbons but not
  many produced

Question 3

equation for ammonia

Answer 3

N2 + 3H2 ⇌ 2NH3

Question 4

e) Describe how to determine the mass of salt that is dissolved in a sample.s

Answer 4

weigh mass of empty evaporating basin
add sample evaporate and measure new mass
weigh mass of of basin after water has been evaporated and determine difference.