how to convert ka to pka without calculator

\u00a9 2023 wikiHow, Inc. All rights reserved. Extended Keyboard. Step 1: Choose the correct formula for Ka K a or pKa p K a for the question. Use the relationships pK = log K and K = 10pK (Equation 16.5.11 and Equation 16.5.13) to convert between K_a and pK_a or K_b and pK_b. pKa is often used in chemistry and biochemistry to describe the acidity of a . Solved Example. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. Best calculator, but other than that. My experience with the app is funtastic till now, really good with little to no ads. Harold Hammer. Video 7 - pH/pOH [H+]/[OH-] Wheel . To convert the Ka value of 7.1 * 10^-7 to the pKa value with no calculator, do we just assume that the power is approximately equivalent to the pKa? pKa = - log Ka - pKa = log Ka 10 - (pKa) = Ka Ka = 10 - (pKa) Consider the reactions below. This article was co-authored by wikiHow staff writer, Christopher M. Osborne, PhD. This is so much faster than looking all over the internet to find an answer to compare to, it may not work on word problems but this does work for any type of number problem. The dissociation constant value for strong acid is as high as 10 7, while for weak acid, it is as low as 10 -12, which is quite tricky to remember. Can I find Ka (or pKa) without a calculator? This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. You can get to just about any number from 2 and 3. concentration=. % of people told us that this article helped them. Unit Converters Unit Converters Energy Temperature Pressure Length Ka Kb pKa pKb New version of unit converters is available . For example log_(10)100 = 2, and log_(10)1000 = 3. The pKa to pH converter calculator is an online tool that can find the pH of a liquid solution using the pKa value and concentration. You can measure the strength of an acid by its dissociation constant K a, which is a ratio formed by dividing the concentration of products by the concentration of reactants: K a = [H30+] [A-]/ [HA] All the reactions happen in water, so it it's usually deleted from the equation. Mathematics is the study of numbers, patterns, and relationships. Take some tips from us and learn How to get pka from ka. You solve this by raising both sides of the original relationship to powers of 10 to get: When pKa is a whole number, such as -7, this operation is easy to perform, but when it contains a fraction, such as 7.5, you may have to look up the value in a table. For example, if pKa = 3.26, then Ka = 10^-3.26. log7 is 0.84, so it's 7 - 0.84 or 6.16. Math can be a difficult subject for many people, but there are ways to make it easier. \(K_a\), the acid ionization constant, is the equilibrium constant for chemical reactions involving weak acids in aqueous solution. Our goal is to make science relevant and fun for everyone. var tr_already_opted_out = "You already opted out from selling your personal information"; It really helps a lot with my homework, even though you have to pay it's worth it and it tells you the steps also. \[ \ce{CH_3CH_2CO_2H + H_2O \leftrightharpoons H_3O^+ + CH_3CH_2CO_2^- } \nonumber\], According to the definition of pH (Equation \ref{eq1}), \[\begin{align*} -pH = \log[H_3O^+] &= -4.88 \\[4pt] [H_3O^+] &= 10^{-4.88} \\[4pt] &= 1.32 \times 10^{-5} \\[4pt] &= x \end{align*}\], According to the definition of \(K_a\) (Equation \ref{eq3}, \[\begin{align*} K_a &= \dfrac{[H_3O^+][CH_3CH_2CO_2^-]}{[CH_3CH_2CO_2H]} \\[4pt] &= \dfrac{x^2}{0.2 - x} \\[4pt] &= \dfrac{(1.32 \times 10^{-5})^2}{0.2 - 1.32 \times 10^{-5}} \\[4pt] &= 8.69 \times 10^{-10} \end{align*}\].