Doing multiple calculations.

**berettagtz** · 04-11-2007, 12:53 AM

I am trying to do some H+ concentration calculations with given pH values. My problem is that I have a lot of pH values, and I don't know how to make excel do all the calculations at once with a given formula. In B cells I have the pH values that are all different, and in C cells I need to calculate the corresponding concentration values.

the formula for any given C cell is: 10^(-pH)

so my question is how do I make excel do the calculations for each C cell without going through each cell individually?

Thanks in advance!

**Paul** · 04-11-2007, 12:57 AM

In cell C2 put the formula

=10^(-B2)

Then, if you hover your mouse over the lower right corner of C2, your cursor will turn into a cross. Click on that corner and drag downward as many rows as you need to copy the formula.

**berettagtz** · 04-11-2007, 01:06 AM

I tried doing that, but when I entered the formula for cell C2 (10^-B2), and copied the formula all the way down, the same formula appeared in each cell.
I wanted something like this:
C2 formula =10^-B2
C3 formula =10^-B3
C4 formula =10^-B4... and so on

so is there a systematic way of doing this?

**Paul** · 04-11-2007, 01:14 AM

That's the point of dragging a formula down, so that the formula stays the same but the cell references adjust automatically (B2 > B3 > B4, etc.)

If your values aren't updating, but the formula is, you most likely have Calculation set to Manual.

Go to Tools > Options > Calculation tab > click 'Automatic' > click OK

**berettagtz** · 04-11-2007, 01:18 AM

it was already set to automatic, I don't know why it shouldn't work. After you highlight the wanted fields, what do you press?? Do you press ctrl shift enter, or is it something else?

**Paul** · 04-11-2007, 01:27 AM

You shouldn't have to press anything.

If you type the first formula into C2, =10^(-B2), and press Enter, that will create the formula for that cell (and show the result). When you drag the fill handle from C2 down 10, 100 or 1000 rows and then let go of the mouse button, it will automatically fill all of those cells with the formula and update the row references (B2 to B3 to B4, etc.).

If you need help with this, post a zipped copy of your workbook to this thread (right-click on your file, choose Send To -> Compressed Folder, to create the .zip file for uploading).