Frequently Wrong Flashcards
(19 cards)
Standard enthalpy of hydration?
Enthalpy change when 1 mol of gaseous ions dissolve in sufficient water.
Standard enthalpy of solution?
Enthalpy change when 1 mol of an ionic substance dissolves in sufficient water.
What type of bonds is radiation absorbed by and what happens to the bonds?
Polar bonds; they rotate faster.
Ester + aqueous sodium hydroxide (reflux)?
Alcohol + carboxylic acid
(HYDROLYSIS)
What happens to pH and Kw as temperature increases?
The Kw increases, and so H+ ions also increase, so the pH decreases.
How to obtain oil from mixture with solid?
- Filter
- Distil
Reaction orders are for reactants/products?
Reactants
When assessing a fuel, talk about (pros and cons):
Pros: recycling, prevents using landfill, renewable, carbon-neutral, fewer stages in production process (if applicable)
Cons: consider the yield, consider solvents used, non-renewable?, deforestation, high cost of transport, large scale plantations = habitat loss.
When giving energy values include…
- the sign
- kJ mol^-1
- 3 s.f.
Effect on delta Ssys when temperature changes?
NO EFFECT
What is a diminishing peak and increasing ?
One that is “fading away” (NOT MS DEFINITION!)
Eg. it is for a bond found in the reactant, but the IR spectroscopy is showing for product, and that bond is not present there.
Increasing peak is the opposite.
What is a partition coefficient?
The ratio of concentrations of a solute in two immiscible or slightly miscible liquids, or in two solids, when it is in equilibrium across the interface between them.
Assumptions for buffer calculation
- Initial acid concentration = equilibrium acid concentration, as dissociation is very small
- Measurements are at standard temperature
- the ions that the acid dissociates into are of equal concentration/moles as they are 1:1 ratio.
When describing effect on delta Ssurr…
MORE positive/negative
OR
LESS positive/negative
DO NOT SAY JUST DECREASES/INCREASES!
Why is it important for clock reaction to have large excess of the ions?
So that they aren’t the limiting reactant.
To work out activation energy for iodine clock reaction, what experimental measurements have to be made?
Temperature and time taken for the solution to turn blue-black.
Why is ____ sparingly soluble?
L-forces between ____ and the solute molecules.
Acid hydrolysis VS alkaline hydrolysis
Acid: reversible reaction, acid is a CATALYST not a reagent, carboxylic acid produced NOT SALT.
Alkaline: NaOH is a reagent, reaction goes to completion, salt of the carboxylic acid is formed.
