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37 Cards in this Set
- Front
- Back
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When is Equilibrium reached? |
When the rate of the forward and backward reaction are the same |
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How do you write an equilibrium expression for an equation? |
Put in the form products/reactants with the concentration of a substance to the power of its stoichiometric coefficient |
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What does K = 1 mean? |
Reactant and Product concentration is equal |
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What does K < 1 mean? |
Reaction favours reactants |
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What does k > 1 mean? |
Reactants favour products |
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What is special about pure liquids and solids in equilibrium expressions? |
They have a constant concentration of 1 |
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What is the effect of an increase in temperature on an endothermic reaction? |
Increased yield of products and K value |
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What is the effect of increasing temperature on an exothermic reaction? |
Decreased product yield and K value |
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How does a catalyst and pressure affect the K value? |
No effect |
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How can the ionisation of water be represented? |
A hydronium ion and a hydroxide ion |
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What does amphoteric mean? Give an example of an amphoteric molecule? |
Can react as both an acid and a base Water |
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What is the ionic product? |
The dissociation constant for the ionisation of water |
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What is Kw |
The ionic product |
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What is the value of Kw at 25º |
1x10^-14 |
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What is the relationship between the hydrogen ion concentration and pH? |
pH = -log 10 (H+) H+ = 10^-ph |
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What is the concentration of the Hydronium and Hydroxide ion at 25ºc? |
10^-7 moll-1 |
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What is an acid? |
A proton donor |
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What is a base? |
A proton acceptor |
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How is a conjugate acid and base formed? |
A conjugate base is formed when an acid loses a protein A conjugate acid is formed when a base gains a proton |
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What is a strong acid/base? |
An acid/base that fully dissociates into an aqueous solution |
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What is a weak acid/base? |
An acid/base that doesn't fully dissociate into aj aqueous solution |
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Name a strong acid and base |
HCl and sodium hydroxide |
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Name a weak acid and base |
Ethanoic acid and Ammonia |
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What forms when a strong acid is mixed with a strong base? |
Neutral solution |
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What forms when a weak acid is mixed with a strong base? |
Alkaline solution |
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What forms when a strong acid is mixed with a weak base? |
Acidic solution |
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What is a buffer solution? |
A solution in which the pH remains constant even if small amounts of acid, base or water is added |
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What is an acid buffer? |
A solution of a weak acid and one of its salts |
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What is an alkaline buffer? |
A solution of a weak base and one of its salts |
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How does an acid buffer work? |
The weak acid provide hydrogen ions, when these are removed by a base the salt of the acid can act as a conjugate base and accept excess hydrogen ions |
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How does a basic buffer work? |
The weak base removes excess hydrogen ions and the salt of the base adds them when they are removed |
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What are indicators? |
Weak acids that that change colour at the end of an acid base titration |
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What is special about the colours of acid indicators and their conjugate bases? |
They're distinctly different colours |
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What affects the colour of an indicator during a reaction? |
The ratio of the concentration of its acid to its conjugate base |
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When does the colour change for an indicator theoretically happen? |
When the concentration of the Hydronium equals the concentration of the equilibrium constant |
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The colour change of an indicator is assumed to be distinguishable when? |
The concentrations of its acid and base differ by a factor of 10 |
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What equation can be used to estimate the pH over which a colour change of an indicator occurs? |
pH = pKin plus or minus 1 |
