Features of transition metals which make them good catalysts

HETEROGENOUS CATALYSTS
Availability of a partially filled 3d subshell which allows for the ready exchange of electrons to and from reactant molecules, thus facilitating the formation of weak bonds with the reactant molecules

HOMOGENOUS CATALYSTS:
Ability to exist in different oxidation states, and relative ease with which they can be converted from one oxidation state to another

Warning signs for a pseudo-first order reaction

• Excess of reactant - since concentration of reactant does not change significantly, so can treat as a first-order reaction
• Solvent is a reactant
• Use of catalyst

Describe the structure of a beta-pleated sheet of a spider silk protein.

Hydrogen bonds form between the C=O group of a peptide in one strand and the N-H group of another peptide in the adjacent strand. R-groups project above and below the beta-pleated sheet.

Outline the procedure of a titration experiment to determine the concentration of ammonia in the organic layer.

NB: Given 0.010 mol dm^-3 hydrochloric acid, methyl orange indicator and lab apparatus commonly used for titration.

1. Fill up a burette with 50.00cm³ of 0.010mol/dm³ HCl
2. Using a dry pipette, transfer 10.0 cm³ of the organic layer into a 250cm³ conical flask.
3. Using a measuring cylinder, add 20 cm³ of deionised water into the conical flask, then add 2-3 drops of methyl orange. 
4. Titrate the resulting mixture against 0.010mol/dm³ HCl until the colour of methyl orange changes from yellow to orange.
5. Repeat the titration until 2 consistent readings are obtained.

Equilibrium constant

Equilibrium constant of salt MX:


For homogenous equation A + B --> C + D (i.e. all in the same state):

Formatted in LaTeX using the CodeCogs editor.

What do you understand by the term 'Dynamic equilibrium'?

Dynamic equilibrium refers to a reversible reaction in which the rate of the forward reaction equals the rate of the backward reaction and there is no net change in the concentration of ions.

Standard electrode potential

The standard electrode potential, E^⦵, of a half-cell is the electromotive force measured at 298 K between the half-cell and the standard hydrogen electrode, in which concentration of any reacting species is 1M/gaseous species is at 1 atm.

Remember to indicate the surrounding temperature when drawing half-cells!

The standard cell potential, E^⦵_cell is the maximum potential difference between two half-cells under standard conditions.