Topic 4 - Biofuels

Question 1

Biogas (made from, made by, how more carbon neutral)

Answer 1

Made from: CO2 and CH4 in equal amounts

Made by: organic material decays in absence of O2 (anaerobic respiration)

How more carbon neutral: organic matter (plants) absorb carbon dioxide that offset the carbon dioxide produced

Question 2

Biodiesel (made from, made by, note on saturation, how more carbon neutral)

Answer 2

Made from: vegetable oil or animal fat (and even cooking oil)

Made by: transesterification

Note on saturation: vegetable oil = unsaturated (one carbon to carbon double bond), animal fat = saturated (no carbon to carbon double bond).

How more carbon neutral: if made from vegetable oil, plants absorb carbon dioxide that offset the carbon dioxide produced

Question 3

Bioethanol (made from, made by, equation, how more carbon neutral)

Answer 3

Made from: Sugar, starch, cellulose

Made by: fermentation

Equation (fermentation of glucose): C6H12O6 (aq) -> 2C2H5OH (aq) + 2CO2 (g)

How more carbon neutral: if made from vegetable oil, plants absorb carbon dioxide that offset the carbon dioxide produced