A catalyst is a substance that increases the rate of a chemical reaction without itself being chemically changed at the end of the reaction
Characteristics of the catalyst:
1. Required in small amounts
2. Do not affect the enthalpy change of the reaction
4. Increase the rate constant of the reaction.
5. Accelerates the reaction, rather than initiate it.
An autocatalyst is a product of a chemical reaction which is capable of acting as a catalyst for the reaction.
A homogeneous catalyst exists in the same phase as the reactants
A heterogeneous catalyst exists in a different phase from the reactants.
12) NJC’09/H1/6 – why Ga then Ca?
19) TJC’09/27 -∆H of vaporization graph implication?
34) CJC’09/6 -AlF3 ionic cpd?
49) HCI’09/14 – why not Al?
63) MI’09/14 – Why transition metals have greater densities than Group II metals?
67) VJC’09/36 – How to read 2nd IE Graph? all elements 1st IE ‘shift’ right from 1st IE Graph?
76) RI’09/26- Why electronegativity between elements in each cpd do not increase?
1) O2 produced because water in excess in aqueous NaCl. Cl2 produced because Cl- in excess in conc NaCl.
2) Cathode Reaction: 4H20 + 4e -> 2H2 + 4OH-
Anode Reaction: 2H20 -> O2 + 4H+ + 4e
3) Chloride is bigger in size as compared to fluorine. It is hence more
easily polarised to form a covalent bond
4) dative bond between nitrogen and boron
5) maximum density of water is at 4degrees. when water cools below 4 degrees, the volume expands. The hydrogen bonds traps the molecules into a rigid 3D structure that aligns water molecules in such a way as to create huge gaps between the molecules