energetics 3.1.4 in all papers

• the heat energy change measured under constant pressure. • its measured in J/KJ per moles.

• standard conditions, 100kpa, 25 degrees/ 298 kelvins.

• a reaction where heat energy is transferred from the surrondings to the reactants, tempreture decreases.

• a reaction where heat energy is released to the surrondings.

• the input of energy, making it endothermic (+).

• mass of water (g) x change in tempreture of water x specific heat capacity of water (KJ). • assuming that all energy from the burning fuel is transferred to the water. • density g of water is 1gcm-3, so 24.5cm3 g of water = 24.5 g

• the output of energy, making it exothermic (-).

• the enthalpy change when 1 mole of a substance is completely burnt in excess oxygen with all reactants being in their standard state under standard conditions.

• the energy required to break 1 mole of a covalent bond averaged across many compounds containing the bond.

• shorter the covalent bond, the stronger the bond. • triple bonds are generally shorter than double or single bonds, so more energy is required to break them resulting in a positive bond enthalpy.

• when one mole of a substance is formed from its constituent elements under standard conditions, all reactants and products being in their standard states.

enthalpy change = sum of the enthalpy change of formation of products - sum of the enthalpy change of reactants.

• states that the enthalpy change during a reaction is independent of the route taken, providing the initial and final conitions are the same. • (the sum of the indirect route = direct route)

• carbon is highly unreactive. • a range of other hydrocarbons could form, meaning we wont get 1 mole of methane.

• glass is a poorer conductor than copper • tripod and gauze would reduce heat transfer

its colourless