Acid and Base Solutions

The negative sign in the formula means that aH must be less than ____.

1

Log functions are used to rescale very large or very small numbers in to value much closer to 1. For pH this scale is between ___ and ___.

1 and 14.

A difference of one unit of the pH scale represents a concentration difference of __, so two units its a concentration of ___.

10, 100

Pure H2O at ___ degree Celsius is recognized as the standard of neutrality between acids and bases because it has a pH value of ____.

25, 7.0

Sample pH scale

Battery acid - below 1 Gastric juice - about 2 Orange juice - between 3 and 4 Milk - pH about 6 Blood - between 7.34 and 7.45 Hand soap- between 9 and 10 Bleach - 12.5

The calculation of pH is based on the activity of hydrogen ions (H+) dissolved in a solution. Specifically the pH range of number is based on the ______ _____.

Logarithmic scale pH = -log (aH)

The pH scale is used to measure the strength of acidic solutions ( which are ___ than 7) and basic solutions(which are ___ than 7).

less than 7, more than 7

EXAMPLE: Suppose the activity of hydrogen ion in a solution is 1 part per thousand 1/1000 (in sceicetific notation, this number = 1 *10^-3

pH = -log (aH) pH=- log (1*10^-3) pH=-(-3) pH =3

Litmus paper will turn ___ for acidic solutions and ____ for basic solutions.

red, blue

Regarding bases, a ___ number of hydrogen ions is associated with a basic solution, and red litmus paper will turn ___ in the presence of a base.

smaller, blue.