Acids, bases and titrations

Acids

Corrosive - break down molecular structure

Taste sour

Have low pH

Can conduct an electric current

Bases

Corrosive - break down molecular structure

Taste bitter

Feel soapy

High pH

Can conduct an electric current

Bronsted - Lowry definition of acids and bases

An acid donates protons to a solutions. Acidic solution has high concentration of protons

Bases accept protons but usually bonded to water (H3O) => high concentration of hydronium ions.

Monoprotic acids

Have one acidic proton to give away.

Note there may be many protons but only one is acidic.

Amphiprotic substances

Can act as either an acid or a base (eg, water)

Polyprotic substances

Can give away multiple acidic protons in a two step process.

Strong acid

Completely dissociates in the solution.

Good at conducting electricity due to charged ions.

Weak acid

Small percent of protons disassociate

Bad at conducting electricity.

Strong bases

Very good at accepting protons

Weak bases

Do not associate with protons at all.

pH

Percentage of Hydronium basically!!

-log[H₃O⁺] or [H₃O⁺] =10^-pH

pOH

percentage of hydroxide ion.

-log[OH^-] or [OH^-] =10^-pOH

Mutliplying concentrations always equals

10^-14

Titration

Used to figure out concentration of a substance in a sample.

Reacting a solution with a known concentration with a solution of unknown concentration.

Aliquot

What is placed in the conical flask

Titre

Comes out of the burette - is measured to see how much is needed to reach point of titration.

pH curves

Helps figure out what indicator to use in the aliquot.

Equivalence point

Where molar ratios of chemical equations are met.

The near straight line on the graph.

0-7 pH

Acidic

7-14

Basic

End point

Where the indicator changes colour in the titration