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Re: How to find pka value
Hello, If I guessed right you are talking about the Chemistry notion of the pKa Let the equilibrium constant be Ka =1.8x10^(-5). Then by definition pKa=-log(Ka) , log in base 10 pKa = - log(1.8x 10^(-5)) First set [MODE] to [COMP] by pressing [MODE] 1. [LOG] [(] 1.8 [x] [SHIFT] [10 to the x] [(-)] 5 [)] . [(-)] The [(-)] key is the change sign key : a small - between parentheses. The last [(-)] sign in the expression takes the negative of the whole calculation to obtain the correct value of the pKa. The value you should find for the above exemple is 4.74
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"ComPuTe". On TI financial calculators you have to press the CPT button before pressing the button for the value you're solving for. (N, I, PV, PMT, or FV). On an HP calculator, you just press the N-I-PV-PMT-FV button without making any entry in order to solve for the desired value.
In Stat mode (press MODE 1) choose the type of data you are working with, e.g linear or quadratic data.
Type in your data points by typing in the x-value pressing (x,y) button, the y-value and CHANGE.
Once you have entered all your data press the ON button.
If you want to predict or interpolate the x value given the y value, you need to type in the y-value and press 2nd F and the ( button. Do you see above ( there is an orange x'?
To predict the y-value, type in the given x-value and then press 2nd F and ) button. Again above this button in orange you will see y'.
If you would like the equation of the line you will see a blue a, b and c above the ( button, ) button and x button. Use the ALPHA to access these functions.
Press [2nd][+] to open (Mem)ory management tool. Select [2:Mem Mgmt,Del] Press [2:Real] Scroll down to reach X; Press the DEL(ete) key. The X-variable will disappear from the list. and the stored value will be replaced by 0. You could also just use 0 [STO>][X,T,Theta,n] to reset value to 0
The CPT button is used on the TI calculators to tell the calculator to compute the value instead of storing one. The HP calculator knows whether you just typed in a number or not, and so it can distinguish without the need for such a key. Thus to calculate a particular value after entering the others, you can simply press the key for that value without bothering with any CPT key.
As for the maturity yield, without knowing exactly which value you want, I'm afraid I can't tell you which key to press. Could you reply to this post and specify that? What key do "they" use on what calculator?
Assuming your two point coordinates are of the form (x1, y1) and (x2, y2).
There are two possible methods:
You can use the slope formula which is commonly known as "rise over run." To do this:
slope = (y2 - y1) / (x2 - x1)
This means that the vertical distance covered by the two points divided by the horizontal distance covered by the two points is equal to the slope.
You can use your calculator's linear regression capabilities:
First step: Press the STAT button (next to the arrow keys toward the top right of your calculator).
Second: Select the first option, Edit...
Third: Under L1, enter your first x value, press enter, enter your second x value, press enter again.
Fourth: Under L2, enter your first y value, press enter, enter your second y value, press enter again.
Fifth: Press the STAT button again. Press the right arrow button to highlight CALC.
Sixth: Select the fourth option LinReg(ax+b).
Seventh: Press 2ND then 1 (L1 should show up on your screen). Then press the comma button (right above the number 7). Press 2ND then 2 (L2 should show up on your screen). Press ENTER.
Eighth: Once you press ENTER, several values will appear. The a value is the slope of the two coordinates.
You need the [EE] key to enter powers of 10 exponents. You need the change sign key [+/-] key. You need the [LOG] key.
pKa: 6.5 [EE] [+/-] 5 [LOG] [+/-] There are two change sign: The first (either before or after the exponent 5), the last is entered after you press the log key , so as to negate (make negative if result is positive, and make positive is result is negative) the value. The result should be 4.1870866 or 4.19
Hi, Let Ka be the acidity constant (acid dissociation constant). The pKa is defined as the negative of the log in base 10 of the acidity constant. pKa= - log_10(Ka) where log_10 is the logarithm in base 10.
To calculate the pKa you use the key labeled [LOG], just above [COS]. Be careful with the negative sign: For that, you use the key [(-)] just above the RCL key. Press the keys in the order specified below
pKa = [(-)] [LOG] number [ ) ] [=]
Although the right parenthesis is not required in this particular case, it is better to accustom oneself to close the parenthesis.
Unlike other brand calculators, HP calculators don't need such a key. After entering the other data, simply press the key for the desired value. For example, to find the future value, simply press the "FV" key.