P1: Make A Standard Solution And Carry Out An Acid Base Titration

Question 1

What is a standard solution

Answer 1

A solution of known concentration

Question 2

How do you make a standard solution

Answer 2

• Use mass balance to measure amount of solid required
• Transfer this to a volumetric flask and rinse the remaining weighing bottle content with distilled water into the flask so no solid is lost
• Add a precise volume of distilled water - Swirl to mix
• Then keep adding water up to the line
• invert the flask a few times to mix

Question 3

How do you do the weighing by difference technique

Answer 3

. Method to weigh materials accurately
. Mass of substance = mass of weighing dish and substance - mass of weighing dish alone

Question 4

What does the pipette and pipette filler do in the reaction

Answer 4

It measures out a set volume of the reactant (either the acid or base) before transferring it to a conical flask

Question 5

What does the burette do in titration

Answer 5

. It can add small volumes of one reactant to the other (until reaction is completed)

Question 6

How do you carry out a titration

Answer 6

. Once the pipette has been used to place one reactant into the conical flask, fill the burette with the other reactant. Record the initial volume.
. Put the conical flask on white tile so it can show slight colour change easily
. Add few drops of indicator to the conical flask eg phenolhalein
. Open burette tap and allow the reactant to flow into the conical flask, swirling it to mix the contents
. Add drop by drop when you think you are near the colour change
. After a slight colour change, close the tap and measure the final volume from the burette
. Repeat until you get concordant results
. Then calculate mean titre

Question 7

Why are acid base indicators used

Answer 7

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

Question 8

What are concordant results

Answer 8

Results within 0.1 cm3 of each other