DP Chemistry Questionbank

Outline why the fuel produced by the reaction in (a) is more suitable for use in diesel engines than vegetable oils.

Deduce the formula of the biodiesel formed when the vegetable oil shown is reacted with the reagents in (a).

State two reagents required to convert vegetable oil to biodiesel.

Explain, in terms of the molecular structure, the critical difference in properties that makes biodiesel a more suitable liquid fuel than vegetable oil.

Determine the specific energy, in kJ$$g⁻¹, and energy density, in kJ$$cm⁻³, of a particular biodiesel using the following data and section 1 of the data booklet.

Density = 0.850 g$$cm⁻³; Molar mass = 299 g$$mol⁻¹;

Enthalpy of combustion = 12.0 MJ$$mol⁻¹.

Coloured molecules absorb sunlight. Identify the bonding characteristics of such molecules.

A mixture of gasoline and ethanol is often used as a fuel. Suggest an advantage of such a mixture over the use of pure gasoline. Exclude any discussion of cost.

Outline the major technical problem affecting the direct use of vegetable oils as fuels in internal combustion engines and the chemical conversion that has overcome this.

State the formula of a fuel that might be produced from the vegetable oil whose formula is shown.

State the formula of a fuel that might be produced from the vegetable oil whose formula is shown.

Outline why biofuels are considered more environmentally friendly, even though they produce more carbon dioxide per kJ of energy than petroleum based fuels.

Outline the major technical problem affecting the direct use of vegetable oils as fuels in internal combustion engines and the chemical conversion that has overcome this.

Deduce the equation for the transesterification reaction of pentyl octanoate, C₇H₁₅COOC₅H₁₁, with methanol.

Outline why the ester product of this reaction is a better diesel fuel than pentyl octanoate.

Biodiesel containing ethanol can be made from renewable resources.

Suggest one environmental disadvantage of producing biodiesel from renewable resources.

This question is about biofuel.

Evaluate the use of biodiesel in place of diesel from crude oil.

Biodiesel containing ethanol can be made from renewable resources.

Suggest one environmental disadvantage of producing biodiesel from renewable resources.

Evaluate the use of biodiesel in place of diesel from crude oil.

Strength:

Limitation:

The structure of chlorophyll is given in section 35 of the data booklet.

State the feature of the chlorophyll molecule that enables it to absorb light in the visible spectrum.

Write the equation for the complete combustion of ethanol.

Explain, including a suitable equation, why biofuels are considered to be carbon neutral.