Question 1: Fractional distillation is a process used to separate mixtures of liquids based on their different boiling points. In the context of crude oil, it allows the separation of various hydrocarbons into useful fractions. The process involves heating the mixture and collecting vapours at different levels of a fractionating column.

Answer: A method to separate liquid mixtures based on boiling points, used to obtain different hydrocarbons from crude oil.

Question 1: What is the main principle behind fractional distillation?

Answer: Separation based on different boiling points of components in a mixture.

Question 2: Why is a fractionating column used in this process?

Answer: To provide a temperature gradient that helps separate liquids based on boiling points.

Question 1: Calculate the boiling point difference if a hydrocarbon distils at 150°C and another at 250°C. Express your answer in °C.

Answer: 100°C

Question 2: A crude oil sample is heated until the fraction with a boiling point of 120°C is collected. If the initial temperature of the crude oil is 25°C, what minimum temperature must the apparatus reach?

Answer: At least 120°C

Question 1: Design a basic experiment to demonstrate fractional distillation of a mixture of two liquids with different boiling points. List the key variables involved and safety precautions.

Answer: Setup involves heating the mixture in a distillation flask connected to a fractionating column and condenser. Variables include temperature, heating rate, and liquid composition. Safety precautions include wearing safety goggles, handling hot equipment carefully, and ensuring proper ventilation.

Question 2: Explain how fractional distillation is used in the petroleum industry to produce fuels like petrol and diesel.

Answer: In the industry, crude oil is heated in large distillation towers. The vapours rise through a fractionating column, where cooler temperatures condense different hydrocarbons at different heights based on their boiling points. This process efficiently separates fractions such as petrol, kerosene, and diesel, which are then further processed for use as fuels.

Question 1: A sample of crude oil yields the following fractions: 25% gasoline (boiling point 40-80°C), 20% kerosene (150-250°C), 30% diesel (250-350°C), and 25% residual heavy oil (above 350°C). Discuss what this data suggests about the composition of the crude oil and its suitability for different uses.

Answer: The crude oil has a balanced mix of light and heavy hydrocarbons, suitable for producing fuels like gasoline, kerosene, and diesel. The residual heavy oil can be used for lubricants or further processing.

Question 1: How does the process of fractional distillation impact the availability and variety of fuels and materials derived from crude oil?

Answer: It allows efficient separation of crude oil into useful fractions, ensuring a variety of fuels and materials are available for different industries and applications.

Question 2: Describe one environmental or safety concern associated with the industrial process of fractional distillation and how it can be mitigated.

Answer: Environmental concerns include emissions of sulphur and greenhouse gases. These can be mitigated by using scrubbers and emission control technologies, and ensuring proper handling of hazardous materials.