Chem 2 - Reaction rates, Salts and Electrolysis - Acids and Alkalis

Revision cards for Acids and Alkali, hope this helps! :]

HideShow resource information

Acids and Alkalis

The pH (Power of Hydrogen - Not needed now, but a fun fact ;-]) scale is a measure of how Acidic or Alkaline a solution is.

The strongest Acid has a pH of 0. The strongest Alkaline has a pH of 14.

A Neutral (Neither Acid nor Alkaline) substance has a pH of 7 (e.g. pure water)

To test the pH of a solution, you use an Indicator. An Indicator is just a dye that changes colour. The dye in the indicator changes colour depending on whether is above or below a certain pH. A Universal Indicator is a combination of dyes which gives the colours Red (Acid) - Purple (Alkaline).

1 of 2

Acids and Alkalis

Acids and Bases neutralise each other. An Acid is a substance with a pH of less than 7. Acids for H+ ions in water. A Base is a substance with a pH of greater than 7. An Alkali is a Base that dissolves in water. Alkalis form OH- ions in water.

The reaction between Acids and Bases is called Neutralisation:

Acid + Base = Salt + Water

It can also be seen in terms of H+ and OH- ions:

H+ + OH- = H20 (Water!! See how this all comes together?)

A Universal Indicator goes green to show a Neutral substance.

State symbols:

These are important, they tell you what physical state a substance is in:

(s) = Solid. (l) = Liquid. (g) = Gas. (aq) = Aqueous (Dissolved in water)

2 of 2


No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Acids, bases and salts resources »