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Description
Flashcards by sophie.holland96, updated more than 1 year ago
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Created by sophie.holland96
almost 11 years ago
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| Question | Answer |
| Rate of Reaction | The change in concentration of a reactant or product per unit time |
| How do you write a rate equation? | rate = k[A][B] (the order in respect to the reactant is shown as the power) |
| Half-life | The time taken for the concentration of the reactant to reduce by half (first order = constant half-life) |
| What does the rate-concentration graph look like for a zero order reactant? | |
| What does the rate-concentration graph look like for a first order reactant? | |
| What does the rate-concentration graph look like for a second order reactant? | |
| Rate-determining step | The slowest step in the reaction mechanism of a multi-step reaction |
| What is the general expression for Kc |
Image:
kc (image/png)
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| Dynamic equilibrium | When the rate of the forward reaction is equal to the rate of the backward reaction, in a closed system. |
| Standard conditions | 298K 100kPa (1atm) 1moldm^-3 |
| Homogenous equilibrium | An equilibrium in which all the species making up the reactants and products are in the SAME state |
| Kc only changes with | Temperature |
| If Kc is more than one the equilibrium shifts to the ... | Right and favours the products |
| If Kc is less than 1 the equilibrium shifts to the... | Left and favours the reactants |
| How is Kc value affected by temperature? | Increase in Kc - rise in temp if the forward reaction is endothermic (equilibrium shift to the right) Decrease in Kc - rise in temp if the forward reaction if exothermic (equilibrium shift to the left) |
| An acid | A proton donor |
| A base | A proton acceptor |
| Alkali | A base that dissolved in water to form OH- ions |
| Neutralisation | A chemical reaction in which an acid and a base react together to produce a salt and water |
| Acid + Carbonate = | salt + carbon dioxide + water ( remember - the ionic equation varies with states of the carbonate) |
| Acid-base pair | A pair of two species that transform into each other by gain or loss of a proton |
| What is the general expression for the acid dissociation constant (Ka)? |
Image:
ka (image/png)
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| How do you work out the pH of a STRONG acid? | [H+] = [HA] (due to complete dissociation) pH = -log [H+] |
| How do you calculate the pH of a WEAK acid? |
Image:
weak_acid_ka.gif (image/gif)
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| What is the expression for the ionic product of water, Kw? |
Image:
kw2 (image/jpg)
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| What are the two methods for calculating the pH of a strong base? | pOH and Kw (remember [OH-] = base concentration due to complete dissociation) |
| What is a buffer solution? | A mixture of a weak acid (HA) and its conjugate base (A-) that minimises pH changes on addition of small amounts of acid or base. |
| General buffer equation. |
Image:
buffer_equ.gif (image/gif)
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| How do you work out the [H+] of a buffer solution? (which can then be used to calculate the pH) |
Image:
buffer (image/png)
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| Define equivalence point | The point in a titration at which the volume of one solution has reacted exactly with the volume of a second solution (there are no reactants in excess) |
| The end point is... | The point in a titration is the point at which the indicator changes colour. (the point at which there are equal concentrations of the weak acid and conjugate base forms of the indicator) |
| What indicator would be used for a strong acid - weak base titration? And state the colour change | Methyl orange Red (acid) --> Orange --> Yellow (base) |
| What indicator would be used for a weak acid - strong base titration? And state the colour change. | Phenolphthalein pink (base) --> colourless (acid) Very sudden change |
| Titration curve: Where is the equivalence point? | |
| Define enthalpy change of neutralisation | The energy change that accompanies the neutralisation of an aqueous acid by an aqueous base/alkali to form one mole of water under standard conditions. |
| Determining enthalpy change of neutralisation. How do you work out the energy change? (m = mass of solutions) |
Image:
q-mct-png (image/png)
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| Calculate enthalpy change of neutralisation. Remember: n = moles of limiting reactant |
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