Flashcards
Enthalpy
Cards in this deck (19)
- 1What is H?Heat energy of a system
- 2ΔH=H(products) - H(reactants)
- 3ΔrHϴΔH when a molar quantity of a compound in a stated chem. equation reactions under ϴ
- 4ΔfHϴΔH When 1 MOLE compound formed from elements under ϴ
- 5ΔfHϴ of an element0KJmol-1 as element -> element = No Δ
- 6ΔcHϴOne mole compound completely reacted w/ O2 under ϴ
- 7ΔneutHϴAcid+Base = 1 MOLE H2O under ϴ
- 8Effect of doubling vol. in ΔneutHϴ on T changeDouble T = double E however spread over twice the volume so no change
- 9How is ΔrHϴ determined from q?q = E gained by surroundings
So ΔrHϴ must be the opposite - 10What is m in reaction btw. 2 solutions?Solution itself is the immediate surroundings
So M of both - 11What is m in solid+solution?m of solution
- 12What is C?'C needed to ^ 1g substance by 1K
- 13What materials have high/low c?Good insulators
Good conductors - 14Inaccuracies w/ experimental ΔcHϴFuel not completely combusted
Evaporation of methanol on wick
Heat loss to surounding other than water - 15Δ btw. experimental and databookExperimental less exothermic due to less efficient energy transfer
- 16How to increase accuracy (2)Use a draught screen could minimise erros of heat loss
Input O2 gas ensure complete combustion - 17Proving that a reactant is in excess in ΔrHϴCalculate n of limiting reagant
This gives you n of excess required
Calculate actual n of excess - 18Calculating ΔrH from bond enthalpiesΔrH=ΣH(r) - ΣH(p)
Involving gaseous atoms of a covalent substance - 19What conditions are required when working out these reactions?All species must be gaseous, therefore it can't be standard if say H2O is involved.
Can still work out the standard, but would need to account for ΔrH of H2O(g) -> H2O(l)
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- User has deleted their subject information Flashcards on Enthalpy, created by Deleted user on 28/04/2018.
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- Created by I Shouldn't be awake · Apr 24, 2018
- Copied by I Shouldn't be awake · Apr 28, 2018
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