pH Review

pH scale

- runs from 0-14 - 7 is neutral (same amount of H+ and OH-) - logarithmic scale so every change in units is by tens

Where is neutral on the pH scale?

7

What are the numbers on a pH scale that could indicate a base?

Above 7 to 14

A student mixes strawberry koolaid and water. A pH indicator is used to measure a pH of 5.4. What type of solution would the strawberry Koolaid be classified?

Acid

In a Koolaid mixture with a pH of 5.4, what must there be more of, hydrogen ions or hydroxide ions?

Hydrogen ions (H+)

A student adds an alka-seltzer table to the koolaid and stirs. The pH now is 8.3 What ions were released by the alka-seltzer table to cause this change?

Hydroxide (OH-)

Is coffee an acid or base?

acid

is bleach an acid, base, or neutral?

base

Acidic

concentration of H+ increases (0-7 on scale)

Basic (Alkaline)

concentration of OH- increases (7-14 on scale)

H+

hydrogen ion

OH-

hydroxyl ion

pH

measure of concentration of H+ and OH- ions

What numbers on the pH scale represent acids?

under 7