3.1.4 Energetics
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
卡片预览 (8 张)
Define the term standard enthalpy of formation.
The enthalpy change when 1 mole of a compound is formed from its constiuent elements in their standard states under standard conditions.
What type of reaction is the standard enthalpy of combustion?
Exothermic ΔH = always -ve
Define the term standard enthalpy of combustion.
The enthalpy change when one mole of a substance is burned completely in oxygen to form its oxides in their standard states, under standard conditions
Give 2 reasons why you would expect the enthalpy of combustion calculated in a laboratory to be different to the theoretical value.
• Substance not burnt completely, incomplete combustion occurs • Some heat energy lost to the surroudings
State Hess’ Law.
The enthalpy change of a reaction is independent of the route taken
What is meant by mean bond enthalpy?
The average energy required to break a specific covalent bond, taken from a range of compounds
What equations are used in calorimetry?
q = mcΔT ΔH = q/n
What occurs in reactions when ΔH is: a) -ve b) +ve
a) more energy released from when bonds are formed b) more energy taken in from when bonds are broken