Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
16 Cards in this Set
- Front
- Back
|
Define a buffer solution |
A system which minimises pH changes when small amounts of acid/bases are added |
|
|
What are the components of a buffer solution |
A weak acid and it's conjugate Base (HA and A-) |
|
|
What are the two methods for preparing buffer solutions |
1) Mixing a weak acid with its salt 2) Partially neutralising a weak acid |
|
|
Equilibria Equation to explain the lack of pH change when an acid is added |
HA < - - > H+ + A- |
|
|
For when an alkali is added: |
H+ + OH- < - - > H2O |
|
|
Typically what are the operating pH's of a buffer if it's pKa is 3 |
2-4 |
|
|
Equation for the concentration of H+ in a buffer solution |
Ka (HA/A-) = H+ |
|
|
Name one common buffer used in the blood |
H2CO3 |
|
|
What is the healthy pH and the range for blood (and name the conditions of high acid/alkali blood) |
7.4, 7.35-7.45 (acidosis and alkalosis) |
|
|
What are the symptoms of acidosis and alkalosis |
1) Fatigue, shortness of breath, shock/death 2) muscle spasms, light headedness and nausea |
|
|
Method to use a pH meter |
Measure a volume of acid into a conical flask Place electrode of pH meter in flask Using a burette, add aqueous alkali, swirling the flask Record pH changes |
|
|
Describe the 3 stages of a pH titration curve (acid to alkali) |
1) There is an excess of acid. The pH increases very slowly as Base is added. 2) Acid and base concentrations are similar. pH increases rapidly when small amounts of Base added in the vertical section. 3) There is an excess of Base. Once again pH increases slowly as Base is added |
|
|
What is the equivalence point and how can you find it on a graph |
The point when the volume of one solution that reacts exactly with the volume of another solution. It is the centre of the vertical section. |
|
|
Define the end point of a titration |
When the indicator contains equal concentrations of HA and A- |
|
|
What are indicators |
A weak acid which has a different colour to its conjugate Base |
|
|
How do you choose an end point |
The pH range of an indicator should contain the pKa of the acid |
