Question 1: Explain in your own words what cracking is and why it is an important process in refining crude oil.

Answer: Cracking is a chemical process that breaks down large hydrocarbon molecules into smaller, more useful ones such as gasoline and diesel. It is important because it increases the amount of valuable fuels produced from crude oil.

Question 1: Describe the main difference between thermal cracking and catalytic cracking.

Answer: Thermal cracking uses high temperature and pressure to break down hydrocarbons, while catalytic cracking uses a catalyst to lower the temperature needed and increase the efficiency of breaking down large molecules.

Question 2: What is a catalyst, and how does it assist in catalytic cracking?

Answer: A catalyst is a substance that speeds up a chemical reaction without being consumed. In catalytic cracking, it helps break down large hydrocarbons more efficiently and at lower temperatures.

Question 1: A large hydrocarbon molecule with a molecular weight of 1000 g/mol is cracked into smaller molecules of average molecular weight 150 g/mol. How many molecules are produced from 1 kg of the large molecule?

Answer: Number of molecules = (mass of large molecule / molecular weight of large molecule) * (Avogadro's number / 1 mol). Calculation: (1000 g / 1000 g/mol) * (6.022 x 10^23 molecules / 1 mol) = 6.022 x 10^23 molecules. Since the total mass remains the same, approximately 6.022 x 10^23 smaller molecules are produced.

Question 2: If a cracking process produces 50% gasoline and 50% diesel from a 2000 kg batch of hydrocarbons, how much of each fuel is produced?

Answer: Gasoline: 1000 kg; Diesel: 1000 kg.

Question 1: List three safety precautions that should be taken when performing cracking in a laboratory or industrial setting.

Answer: Use proper protective equipment (gloves, goggles, lab coat), handle high temperatures and flammable gases carefully, and ensure proper ventilation and fire safety measures are in place.

Question 2: Identify the variables that can be controlled and those that are constant during a catalytic cracking experiment.

Answer: Controlled variables include temperature, pressure, and catalyst type. The constants are the initial hydrocarbon feedstock composition and reaction time.

Question 1: A refinery processes 10,000 barrels of crude oil. After cracking, the yield of gasoline increases from 20% to 35%. How many additional barrels of gasoline are produced due to cracking?

Answer: Initial gasoline: 10,000 x 20% = 2,000 barrels; post-cracking: 10,000 x 35% = 3,500 barrels. Additional gasoline produced = 3,500 - 2,000 = 1,500 barrels.

Question 2: In a cracking process, the conversion rate of heavy hydrocarbons to lighter hydrocarbons is 85%. If 500 kg of heavy hydrocarbons are processed, how much lighter hydrocarbons are produced?

Answer: Lighter hydrocarbons produced = 85% of 500 kg = 0.85 x 500 kg = 425 kg.

Question 1: Explain how cracking has improved the availability of gasoline for automobiles.

Answer: Cracking converts large, less useful hydrocarbons into smaller, more useful ones like gasoline, increasing supply and making fuel more affordable and accessible for vehicles.

Question 2: Discuss one environmental impact of cracking and how industry is addressing it.

Answer: Cracking produces greenhouse gases and pollutants. Industry addresses this by using catalysts to reduce energy consumption, implementing cleaner technologies, and installing emissions control devices.