# Formulas for A2 Chemistry

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• Created by: Simon_Q
• Created on: 19-02-14 14:39
What is the general format for the formula for the rate of a reaction?
Rate= k(A)^n (B)^m Where n and m are the number of mols of each reactant and A and B are each reactant. The brackets should also be square to show concentrations.
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The pH of a strong acid can be worked out using what formula?
-log(H^+)
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You can rearrange the rate equation to find k. What are the units for k? (don't worry too much about the powers on it for now)
mol^-1 dm^3 s^-1
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Using the formula -Ea/ R = gradient, what is Ea?
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What is R?
8.134
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Standard entropy of the system is what…?
Sum of the standard entropy of the products - the sum of the standard entropy of the reactants
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pH of a strong base is…?
-log( Kw/(conc of OH)) where Kw is the water constant.
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What is Kw?
1x10^-14
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Partial pressure can be found with what formula?
(moles/ total moles) x total pressure (P)
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moles/(volume/1000) is the formula to find what?
Concentration (in dm^3)
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As well as strong acids and bases there are weaker ones. What formula can you use to find the pH of a weak acid?
-log((HAxKa)^(1/2)) where ^1/2 is the same as square rooting and HA is concentration and Ka will be given.
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Similarly what formula can be used to work out the pH of a weak base?
14-pOH (you can work out pOH the same way as you would pH)
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-(deltaH/ T) is the formula for what?
Standard entropy of the surroundings.
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Do you add or subtract the standard entropy of the surroundings and system to find delta S total?
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## Other cards in this set

### Card 2

#### Front

The pH of a strong acid can be worked out using what formula?

-log(H^+)

### Card 3

#### Front

You can rearrange the rate equation to find k. What are the units for k? (don't worry too much about the powers on it for now)

### Card 4

#### Front

Using the formula -Ea/ R = gradient, what is Ea?

What is R?