pH, the meaning of the pH scale, acids and bases and buffer solutions

We did an experiment in lab on pH,acids and bases but he really didn't go over it w/ us and wants us to answer the self test questions on our lab manual.
Kindly help me answer the ff questions:

1) The pH scale is a logarithmic scale. This means that the difference between 2 pH units is really a factor of 10. With this in mind, answer the following questions:
* i really couldn't understand what it means when they say, "this means that the difference between 2 pH units is really a factor of 10"

        a. how many times more acidic is a solution whose pH =1 compared to a solution whose pH is 5?
        b. how many times more basic is a solution whose pH=12 compared to a solution whose pH = 10?

2) Write a list showing the advantages and disadvantages of obtaining the pH of a substance using
        a. a pH meter
        b. pH paper (or universal indicator)

      -- maybe you can give me more reasons *wink*

3. Complete the ff equations for the addition of an acid and base to phosphate buffer solution.

        a. (HPO4)-2  + H1+  -->
        b. (H2PO4)-1  + (OH)1-  -->

thanks so much!!! i would really appreciate it!

Not to give away the farm or anything but a logarithmic scale is geometric. In this scale a whole number increase is a power of 10. This is much like the Richter Scale used to measure strength of earthquakes or decibel scale for sound. Each whole number increase represents a 10-fold actual increase, an increase of 2 indicates a 10x10 increase (102).

A scale or colored paper, gee I don't know. What do you think? ;)

Part three - well you really should think this through. It's not that difficult.



anybody willing to help? and explain the whole thing? our teacher just sucks! thanks!