Cracking Crude Oil and Alkenes.

Which of the following statements about crude oil is accurate?

• Crude oil is a pure substance made up of one type of hydrocarbon.
• Crude oil can be separated into different hydrocarbons using fractional distillation.
• Crude oil is only composed of alkenes.
• Crude oil cannot be used to produce fuels.

What is a key characteristic of shorter hydrocarbons compared to longer ones?

• They are less flammable.
• They have a higher boiling point.
• They are more viscous.
• They are more flammable and make better fuels.

What is the primary purpose of the cracking process in hydrocarbon chemistry?

• To separate crude oil into different fractions
• To break down longer hydrocarbons into shorter, more flammable ones
• To convert alkenes into alkanes
• To increase the viscosity of hydrocarbons

What is the significance of thermal decomposition in the cracking process?

• It involves heating to break down larger molecules into smaller ones.
• It cools down the hydrocarbons to prevent reactions.
• It enhances the viscosity of the hydrocarbons.
• It allows hydrocarbons to be mixed with water.

Why is cracking important in the production of useful hydrocarbons?

• It increases the viscosity of crude oil.
• It eliminates the need for fractional distillation.
• It produces shorter, more useful hydrocarbons from longer chains.
• It converts all hydrocarbons into solid forms.

Which of the following best describes catalytic cracking?

• Heating hydrocarbons without any additional substances
• Mixing hydrocarbons with water to create a reaction
• Vaporizing long chain hydrocarbons and passing them over a catalyst
• Heating hydrocarbons with steam at low temperatures

Which method of cracking involves mixing hydrocarbons with steam?

• Fractional distillation
• Steam cracking
• Thermal cracking
• Catalytic cracking

When cracking decane (C10H22), which of the following products is formed?

• Only an alkane with the formula C8H18
• An alkane with the formula C10H22
• Ethene (C2H4) and an alkane with the formula C8H18
• Only ethene (C2H4)

What is the relationship between the number of carbon and hydrogen atoms in the products during cracking?

• The number of carbon atoms decreases while the number of hydrogen atoms decreases.
• The number of carbon and hydrogen atoms remains constant.
• The number of carbon atoms decreases while the number of hydrogen atoms increases.
• The number of hydrogen atoms always exceeds the number of carbon atoms.

How do alkenes differ structurally from alkanes?

• Alkenes are saturated, while alkanes are unsaturated.
• Alkenes have only single bonds, while alkanes have double bonds.
• Alkenes have a triple bond, while alkanes have single bonds.
• Alkenes have at least one double bond, while alkanes have only single bonds.