22 Thermochemistry: SAQ2

Hess's Law states that the heat change of a reaction only depends on the initial and final states, regardless of the reaction route.

Isomerisation

Breaking down large molecules into smaller ones with higher octane numbers

<p>Dehydrocyclisation</p> Signup and view all the answers

<p>Steam reforming is a process that produces CO and 3H₂ from water and methane.</p> Signup and view all the answers

<p>Electrolysis of water is a process that produces hydrogen at the cathode and oxygen at the anode.</p> Signup and view all the answers

<p>Steam reforming and electrolysis of water</p> Signup and view all the answers

<p>An exothermic reaction, and ∆H is negative.</p> Signup and view all the answers

<p>The octane number is a measure of a fuel's tendency to resist auto-ignition, and the two compounds used as references are 2,2,4-trimethylpentane (octane number = 100) and heptane (octane number = 0).</p> Signup and view all the answers

<p>The heat of combustion of a substance is the heat change in kilojoules when one mole of the substance is completely burned in excess oxygen.</p> Signup and view all the answers

<p>The Law of Conservation of Energy states that energy cannot be created or destroyed, but can change from one form to another.</p> Signup and view all the answers

<p>The bond energy is the amount of energy in kJ needed to break one mole of bonds of the same type, all species being in the gaseous state.</p> Signup and view all the answers

<p>The three factors that affect the octane number of a molecule are chain length, degree of branching, and cyclic structure.</p> Signup and view all the answers

<p>The kilogram calorific value is the amount of heat energy produced per kg of fuel.</p> Signup and view all the answers