4.2 Acid-Base Titrations

Question 1

What is a titration

Answer 1

A technique used to accurately measure the volume of one solution that exactly reacts with another solution

Question 2

What can titrations be used for?

Answer 2

-Finding the concentration of a solution
-Identifying unknown chemicals
-Finding the purity of a substance

Question 3

What is a standard solution?

Answer 3

A solution of known concentration and volume.

Question 4

What equipment is used to make up a standard solution?

Answer 4

A volumetric flask

Question 5

State how to prepare a standard solution

Answer 5

1- Solid is weighed accurately
2- Solid is dissolved in a beaker, using less distilled water than will be used to fil the volumetric flask to the mark
3- Solution is transferred into a volumetric flask, any traces of the solution are rinsed with distilled water
4- Flask is filled to the graduation line by adding distilled water a drop at a time, until the bottom of the meniscus lines up exactly
5- Volumetric flask is inverted several times to mix the solution thoroughly

Question 6

What equipment is used to titrate an acid against a solution of a base?

Answer 6

Pipette and a burette.

Question 7

How can you get the closest accurate titre value?

Answer 7

Repeat the titres until 2 values are within 0.1cm^3 of eachother.

Question 8

What should you know from the results of a titration?

Answer 8

-Both the concentration and reacting volume of one o fthe solutions
-Only the reacting volume of the other solution

Question 9

What should you do once you have the results of a titration? (Calculations)

Answer 9

-Work out the amount, in moles, of the solute in the solution for which you know both the volume and conc
-Use the equation to work out the amount in moles of the solute in the other solution
-Work out the unknown information about the solute in the other solution (conc)

Question 10

State the instructions for an acid-base titration.

Answer 10

1- Add a measured volume of one soluton to a conical flask using a pipette
2- Add the other solution to a burette, and record the initial burette reading to the nearest 0.05cm^3
3- Add a few drops of an indicator to the solution in the conical flask
4- Run the solution in the burette into the solution in the conical flask, swirling the conical flask to mix the solutions. At the end point, the indicator changes colour, indicating when the volume of one solution has exactly reacted with the other
5- Record the final burette reading (volume of solution added to the flask from the burette is called the titre)
6- A quick, trial titration is carried out first to find the approximate titre
7- A titration is repeated accurately, until 2 accurate titres are concordant