CHEM 108: CHAPTER 16
13 Cards in this Set
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What is the regular definition of Ka?
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It's usually products/reactants.
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What is the other form of Ka?
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It is equal to the concentration of water (nearly constant) multiplied by Kc, the equilibrium constant
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What are the two ways to experimentally determine Ka?
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1: Use some colligative property of solution to find the degree of ionization/percentage of molecules that reacted with water.
2. Find the pH of the weak acid to determine H3O concentration.
Do Example 16.1
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If Ka is known, what can be calculated? (There are three.)
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The concentrations of:
1. HA (Weak acid)
2. A- (Ionized form of acid)
3. H3O+ (Hydronium conc.)
(All at equilibrium)
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What does a large Ka mean, given concentration?
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Means a big degree of ionization
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When given a Ka, what does a more dilute concentration mean?
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It means that the degree of ionization is greater.
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How does one know when to omit the x for the change in the concentration of the weak acid? What do you do if it isn't okay to omit x?
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If Ca (Initial concentration)/Ka (Acid dissociation constant) is greater than 100, the assumption that x is negligible is valid.
Use the Quadratic formula.
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What is a polyprotic acid? Give an example.
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A polyprotic acid releases multiple protons that are transferred to water. An example would be H2SO4. Since there are two H's, it'll lose them one at a time.
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If an acid is polyprotic, what must be considered?
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There will be multiple equilibria equations that must be written. One for the dissociation of the first H and other ones for the dissociation of the rest.
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Looking at the Ka values for a polyprotic acid, how does the Ka of the first dissociation compare with each subsequent one?
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The Ka of the first one is significantly larger than the second. This means that as one proceeds to remove H from the compound, it becomes harder to do so.
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What happens basically in a base ionization reaction?
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...
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What is the formula for the base-ionization constant?
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Same as one for acid, product of the products/product of the reactants (concentration wise)
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Hydrolysis
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Hydrolysis is the addition of acid/base to water and the splitting of it (lysis) so that either the acceptance or donation of a proton occurs.
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CHEM 108: Terms