Needing help with addint the power of into calculator

Use the +/- key (located just right of the decimal point key).

For example, to enter 1.2 times 10 to the -3 power, press 1 . 2 EE +/- 3

1*10^(-3)

Because you're using -3 as an exponent, you need to put the whole thing in the parentheses.

Make sure you use the +/- key and not the - key to enter negative numbers. For your example, press 2 SHIFT [y^x] 1 0 +/- =

Refer to the "Negative Numbers" in the "Getting Started" section of the manual (page 24 in my copy).

To enter an exponent, positive or negative, use the EE (Enter Exponent) key (the shifted function of the , key just above the 7 key). Do 5 2ND [EE] (-) 1 0 / 5 2ND [EE] (-) 1 0 ENTER and you'll see 1.

What I think you're doing (I can't be sure without seeing your keystrokes) is calculating
5*10^-10/5*10^-10 which is interpreted as (5*10^-10/5)*10^-10, which indeed is 10^-20.

Use the (-) key for negative numbers (not just exponents) instead of the - key. The - is to subtract one value from another, (-) is to input a negative value.

Use the log function (common logarithm). See screen capture for markings on key.

To evaluate the negative of a logarithm
Enter the number (argument) of the logarithm
Press the = key to have it calculated.
While result is still displayed, press the sign change key or (+/-).

Beware that -log(number) is not necessarily a negative value.

Another way to calculate -log is to use the relation
log(1/a)=-log(a) .

Your example

3 [EXP] [(] [+/-] 2 [) ] [LOG][=] [+/-]

[EXP] is the key to enter exponent of a power of 10 :It is a shortcut, so no 10 is entered. Respect the key sequence above.
[ (] left parenthesis to prevent ambiguity due to the negaticve exponent. Just a security.
[)] is the enclosing right parenthesis
[+/-] is the Sign Change key

You compute the negative of a logarithm the same way you compute the negative of anything else. However, do you really mean the antilog (inverse logarithm)? Use 2ND [e^x] for the natural antilog, 2ND [10^x] for the common antilog.

For negative exponents, as well as negative anything, use the (-) key next to the decimal point. For your example, 1 EE (-) 6

Hello,
This post answers two questions

1. How to obtain the concentration knowing the pH?
2. How to obtain the pH knowing the concentration

If you are not interested in the theory, jump to the examples at the end of the post.

As you well know the pH is the negative of the log in base 10 of the H+/H3O+ ion concentration. If we use [H+] to represent that concentration, then pH=-log[H+].
To obtain the [H+] you need to calculate the antilog. You write the definition in the form log[H+] =-pH and then calculate 10 to the power of each member. The equality remains valid as both members are treated similarly. Thus
10^( log[H+] ) = 10^(-pH)
Since raising 10 to a power is the inverse function of taking the log in base 10, 10^(log(x))=log(10^(x)) = x (they are inverse of one another), you are left with

[H+]=10^(-pH)

Your calculator has a function [10 to x] accessed by pressing the [2nd] function key. To use it you must enter the negative value of the pH, press the [2nd] function key then the [10 to x], then the = key to get the result (concentration)
Examples

1. Let the pH=5.5, what is the H+ concentration?

With [(-)] being the change sign key, then
[H+]:[ (-) ] 5.5 [2nd][10 to x] [=]
The result is 0.000003162 or 3.16 x 10^(-6)

Calculating the pH

Shortcut:
For all H+/H3O+ concentrations of the form 1.*10^(a) where a is an integer number between 0 and -14, the pH is the negative value of the exponent.
Concentration =10^(-3), pH=3
Concentration=10^(-11), pH=11

For other concentrations such as 3.567*10^(-8), one cannot use the shortcut above, but have to calculate the log of the concentration

[H+/H3O+] = 3.567*10^(-8)
pH= - log(3.567*10^(-8))
This is keyed in as follows (to minimize the number of parentheses)

8 (-) [2nd][10 to x] [*] 3.567 [LOG] [=] (-)
Here you have two (-) change sign, the first is entered after the exponent of 10, the other at the end of the calculation to take the negative of the displayed result. You may notice that it is entered in the reverse order of the defining relation - log(3.567*10^(-8)).
To verify your calculation, the result is 7.447696891 or just 7.45
If you have a problem with the first (-) try entering it before you type in 8.


Hope it helps and thank you for using FixYa
And please, show your appreciation by rating the solution.

Use the ^ key to insert a power (it's located above the division key) then put a negative power by typing the negative key (located at the very bottom right of the keypad next to the ENTER key) and then the number of the power.

10^-3

If this doesn't give the right result, put the negative power in parentheses. I can't remember off hand if you need to do that or not.

10^(-3)

Hi....by looking at the date you posted this question, you may have already found the answer, but just in case you haven't......the procedure for adding and subtracting on these calculators is completely opposite of a regular calculator. On a regular calculator, you would input 4 - 4 = 0. On these type of calculators, a number's positive or negative status is keyed in AFTER the number, instead of before it. Therefore, you input 4 + 4 - (notice you DO NOT input = at the end, but if you are in print mode, you will need to hit your total key, which looks like an asterisk, where the = would normally be, in order for the final value of your calculations to print on the paper tape.

Multiplication and division equations are done exactly as they are on a regular calculator....4 x 4 = 16.

Hope this helps. If you have your owners manual, it should also give you some examples of how to perform calculations with your calculator.