Energy Flashcards
Energy:
Enthalpy = Energy
Written as ΔH ( delta H )
Energy:
ΔH = (Enthalpy of Products) - (Enthalpy of Reactants)
Energy: Reaction Profile
Exothermic
(exit)
- Heat given out
- Enthalpy of reactants > products
- ΔH = negative
i.e. respiration
Energy: Reaction Profile
Endothermic
(into)
- Heat taken in
- Enthalpy of reactants < products
- ΔH = positive
i.e. photosynthesis
Energy:
Activation Energy
(Ea)
Minimum heat needed to cause a successful reaction
Energy:
Standard Conditions
Completing a lab with same conditions
↳ creates accurate results
Energy: Standard Conditions
- Pressure (100kPa)
- Temperature (298K)
- Concentration ( 1 mol dm-3)
Energy:
ΔH of Reaction
Energy change that accompanies a reaction with MOLAR QUANTITIES shown in the CHEMICAL EQUATION, under standard conditions, with all species in their standard states
Energy: Notes on
- State what the mole ratio is
- Add states at room temp
Energy:
ΔH of Formation
Energy change when 1 MOLE OF A COMPOUND is formed from its ELEMENTS in their standard state under standard conditions
Energy: Notes on
- Produces 1 mol of compounds
Energy:
ΔH of Combustion
Energy change when 1 MOLE of a substance BURNS IN OXYGEN under standard conditions
Energy: Notes on
- Alkane has to have exactly 1 mol
- Combustion products are formed
Energy:
ΔH of Neutralisation
Energy change when an ACID & ALKALI react to form 1 MOLE OF WATER under standard conditions
Energy:
Colorimetry
Involves heating/cooling known amounts of water
Energy:
q = mcΔT
- q = Heat Energy (J)
- m = Mass (g)
- c = SHC (JK)
- ΔT = Change in Temp (K)
Energy:
SHC of water is
4.18 J g K-1
Energy: Causes for
Anomalies
Between LV & EV
- Use of sophisticated apparatus
- Amount of times results were repeated
- SETUP: was heat lost??
- Conditions were not standard
Energy:
Incomplete combustion of methanol produces carbon & carbon dioxide
Identified through blacksmoke
Energy:
Hess’ Law
Total enthalpy change of a reaction is always the same no matter which route is taken
Energy: Calculating Enthalpy change with
Energy: Calculating Enthalpy change with
Energy:
Bond Enthalpy
Energy needed to break a bond
(endo)
Energy: Bond Enthalpy
Exothermic
(-ΔH)
Bond-making
