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37 Cards in this Set
- Front
- Back
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Delta s surr = |
- H / T (h in joules and t in k) |
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S total = |
S sys + s surr |
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If s total is positive |
The reaction is spontaneous |
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If s tot is 0 |
Reaction is in equilibrium |
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If S total is negative |
The reaction does not take place |
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Enthalpy of solution |
The enthalpy change when 1 mole of an ionic dissolves in water until further dilution causes no enthalpu change |
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Acids |
Are good proton donors |
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Bases |
Are good proton acceptors |
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OH- conjugate acid |
H2O |
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H2SO4 conjugate base is |
HSO4 - |
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pH = |
-log [H+] |
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K w= |
[H+][OH-] |
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Weak acids are |
Poor proton donors |
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Ka is the |
Acid dissociation constant |
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Kc= (formula) |
[H+] salt/acid |
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p K a |
- log K a |
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K a. For weak acids = |
Assume that the concentration of salt and H+ is the same so [H+]^2 / [HA] |
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Indicators in equilibrium the K a = |
[H+] because the salt and acid are the same (in equilibrium) |
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Indicators in equilibrium pK a = |
pH |
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Buffers are a mixture of |
Weak acid and its salt or a weak base and its salt |
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Buffers [H+] = |
K a x [acid] / [salt] |
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Coarse tuning vs fine tuning |
The K a value of the buffer, fine tuning is the ratio of salt to acid |
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Delta H LE = |
The enthalpy change when 1 mole of solid is formed from its gaseous ions. Value is always negative. Lattice enthalpy increases as charge on the ions increases and the ionic radius decreases . Ions in solution are SOLVATED , in water it is called hydration. |
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Delta H hyd= |
The enthalpy change when 1 mole of gaseous ions are dissolved to an infinite dilution in water .(solvation if not water) . It is always negative and it increases as charge increases and ionic radius decreases. |
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Enthalpy of solution delta H solution is |
The difference between the hydration enthalpies of ions and the lattice enthalpy . = H hyd cations + anions - H LE |
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Will it dissolve? |
If delta H solution is negative or if there is an increase in entropy . |
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Specific heat capacity = |
The number of joules required to raise the temperature of 1 gram of the substance by 1 degrees Celsius. J g-1K-1. |
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Types of kinetic energy |
Translational , rotational, vibrational |
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Energy is quantised |
Molecules are restricted to a range of precise values of energy levels |
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Entropy is |
A measure of the number of ways of arranging molecules and the number of ways of distributing their quanta of energy . |
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Delta S reaction (or system) |
Sum of entropies of products - the sum of entropies of reactants. |
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NO3 |
- |
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SO4 |
2- |
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CO3 |
2- |
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OH |
- |
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NH4 |
+ |
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HCO3 |
- |
