pH Indicators (Litmus, Phenol Red, Universal Indicator)

Litmus
There are two types of Litmus Paper: Red and Blue. Red Litmus Paper turns blue when it is dipped in a solution of pH 8.3 or more (stronger alkalis), and Blue Litmus Paper turns red when dipped in a solution of pH 4.5 or less (stronger acids)
Phenol Red

Phenol Red turns yellow when it is dipped [...]

pH Reactions – Blowing into Water

When universal indicator is placed into water, it displays a pH of roughly 7. When one blows through a straw into the water, the pH drops to 6. This is because of the Carbon Dioxide the action of blowing into the water adds to the solution.
—————-
Just heard: George Michael – I Want Your Sex (Parts [...]

Rate of Reaction

Different chemical reactions take place at different speeds
Many, particularly those involving solutions, seem to take place instantaneously
Others take rather longer; the conversion of plant material to coal can take millions of years
As the reaction progresses, the concentration of the reactants decreases, and that of the products increases, but continuous measurements of concentration is not easy
Quantities [...]