2 Matching Annotations
1. Sep 2022
2. chem.libretexts.org chem.libretexts.org
1. The frequency factor determines the maximum rate of collisions, is a function of particle size, concentration and the rate of diffusion. The steric factor accounts for orientation, in that not all collisions have the correct orientation to result in a reaction, (see video 14.6.214.6.2\PageIndex{2}). The rule of thumb is that the more symmetric a molecule the larger the steric factor (a value of 1 means there is no effect, and the pre-exponential is determined by the collision frequency) and the more complicated a molecule, the smaller the steric factor (which is less than one), because only a fraction of the collisions have the correct orientation.

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3. Aug 2022
4. chem.libretexts.org chem.libretexts.org
1. Now if you think about it, the cation repels the positive end of the dipole and attracts the negative end, so the negative end is closer to the cation than the positive end. This means the attractive energies are greater than the repulsive (as they are closer together, the r of coulombs law is in the denominator of eq. So the net force is attractive since since the radius (in the denominator of Coulombs Law, Equation 11.2.111.2.1\ref{11.2.1}) for the +/- attraction is smaller than the radius for the +/+ repulsion. This difference is greatest when the polar molecule is "touching" the cation, and as they become further separated the relative differences in the radii between the two interactions become less, and at great distances they become equal, making these short range forces. This can be understood by looking at

Negative end of dipole closer to cation than positive end. Greatest difference is when the cation is “touching” cation, and the interactions become less as they get further apart-however at great distances they become equal which makes them short range forces.