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  2. Taft equation - Wikipedia

    en.wikipedia.org/wiki/Taft_equation

    where ⁡ is the ratio of the rate of the substituted reaction compared to the reference reaction, ρ* is the sensitivity factor for the reaction to polar effects, σ* is the polar substituent constant that describes the field and inductive effects of the substituent, δ is the sensitivity factor for the reaction to steric effects, and E s is ...

  3. Power factor - Wikipedia

    en.wikipedia.org/wiki/Power_factor

    The power factor in a single-phase circuit (or balanced three-phase circuit) can be measured with the wattmeter-ammeter-voltmeter method, where the power in watts is divided by the product of measured voltage and current. The power factor of a balanced polyphase circuit is the same as that of any phase. The power factor of an unbalanced ...

  4. List of unsolved problems in chemistry - Wikipedia

    en.wikipedia.org/wiki/List_of_unsolved_problems...

    RNA folding problem: Is it possible to accurately predict the secondary, tertiary and quaternary structure of a polyribonucleic acid sequence based on its sequence and environment? Protein design : Is it possible to design highly active enzymes de novo for any desired reaction?

  5. Leading and lagging current - Wikipedia

    en.wikipedia.org/wiki/Leading_and_Lagging_Current

    Angle notation can easily describe leading and lagging current: . [1] In this equation, the value of theta is the important factor for leading and lagging current. As mentioned in the introduction above, leading or lagging current represents a time shift between the current and voltage sine curves, which is represented by the angle by which the curve is ahead or behind of where it would be ...

  6. Steric effects - Wikipedia

    en.wikipedia.org/wiki/Steric_effects

    In organic chemistry, steric effects are nearly universal and affect the rates and activation energies of most chemical reactions to varying degrees. In biochemistry, steric effects are often exploited in naturally occurring molecules such as enzymes , where the catalytic site may be buried within a large protein structure.

  7. Zeta potential - Wikipedia

    en.wikipedia.org/wiki/Zeta_potential

    In the colloidal chemistry literature, it is usually denoted using the Greek letter zeta (ζ), hence ζ-potential. The usual units are volts (V) or, more commonly, millivolts (mV). From a theoretical viewpoint, the zeta potential is the electric potential in the interfacial double layer (DL) at the location of the slipping plane relative to a ...

  8. Non-linear effects - Wikipedia

    en.wikipedia.org/wiki/Non-linear_effects

    Therefore, the reactive catalytic species should decrease in concentration, leading to an overall slower reaction rate. If the correction factor is less than one, the reaction displays an asymmetric depletion, also known as a negative non-linear effect. In this scenario, the heterochiral catalyst is relatively more reactive than the homochiral ...

  9. Stark effect - Wikipedia

    en.wikipedia.org/wiki/Stark_effect

    The Stark effect is the shifting and splitting of spectral lines of atoms and molecules due to the presence of an external electric field. It is the electric-field analogue of the Zeeman effect , where a spectral line is split into several components due to the presence of the magnetic field .