RP 01- Making up a standard solution and carrying out an acid-base titration

Chemistry

What is a standard solution?

A solution of known concentration

How do you make a standard solution?

Measure, using a balance, the mass of solid required

Transfer this into a volumetric flask and rinse the remaining content (with distilled water) into the flask so no solid is lost

Add a volume of distilled water to dissolve the solid and swirl to mix

Add more distilled water up to the line on the volumetric flask and invert multiple times to mix

What is the weighing by difference technique?

Mass of substance = mass of weighing dish and substance - mass of dish after substance has been transferred

What equipment is used to carry out a titration?

A pipette and pipette filler are used to accurately measure out the volume of a reactant before transferring it to a conical flask

A burette is used to add small volumes of the other reactant to the one in the chemical flask until the reaction has reach completion

How do you carry out a titration?

Use a pipette to place one reactant into a conical flask with a white tile underneath it, fill the burette with the other and record the initial burette volume

Add a few drops of indicator to the conical flask

Open the burette tap and allow the reactant to flow into the conical flask, swirling it to mix the contents

Close the burette tap once the expected colour change occurs

Record the final burette volume

Repeat until you get concordant results, then calculate a mean titre

Why are acid-base indicators used?

To detect when a reaction reaches completion, usually by the presence of a colour change

What are concordant results?

Titres that are within 0.1 cm^3 of each other