Apparatus used in volumetric analysis

Question 1

What is volumetric analysis?

Answer 1

It involves reacting together volumes of solutions.

Question 2

How is the volume of a solution determined?

Answer 2

The volume of a solution is determined by reacting that solution with another solution of known concentration.

Question 3

In a titration, what is the stage when the two solutions just react completely with each other called?

Answer 3

It is called the equivalence point of the titration.

Question 4

What is the equivalence point?

Answer 4

the stage when the two solutions just react completely with each other

Question 5

What is the end point of a titration?

Answer 5

When the equivalence point is shown by an indicator it is called the end point of the titration.

Question 6

When the equivalence point is shown by an indicator it is called what?

Answer 6

the end point

Question 7

Define titration

Answer 7

A titration is a laboratory procedure where a measured volume of one solution is added to a known volume of another solution until the reaction is complete

Question 8

What is the flaw of the graduated cylinder? When should it be used?

Answer 8

It is not particularly accurate and should be used only for measuring out approximate volumes of liquids.

Question 9

What should you do before using a graduated cylinder?

Answer 9

Rinse it out with deionised water

Question 10

What is the volumetric flask designed for?

Answer 10

It is designed to contain a definite volume of solution

Question 11

What should be done with the volumetric flask before being used?

Answer 11

It should be rinsed out with deionised water.

Question 12

What should be done with the volumetric flask when near the graduation mark?

Answer 12

The last few cm^3 should be added carefully using a small dropper till the bottom of the meniscus is in line with the mark

Question 13

How do you mix a volumetric flask?

Why is it done this way?

Answer 13

It must be mixed well by inverting the stoppered flask about 20 times.
This ensures the solution is uniform throughout and is a homogeneous mixture

Question 14

What is a pipette designed to do?

Answer 14

To deliver only an exact volume of solution

Question 15

How is a pipette used properly?

Answer 15

Previously rinsed out with deionised water, rinsed with whatever is being pipetted, read meniscus mark at eye level, bottom of meniscus on mark, do not blow out last drop from pipette, allow drainage time, touch tip against inside wall of the conical flask

Question 16

How is a burette used properly?

Answer 16

Previously rinsed out with deionised water, rinsed with whatever is being pipetted, read meniscus mark at eye level, bottom of meniscus on mark, keep burette vertical, remove funnel before adjusting to zero

Question 17

When filling a burette with potassium permanganate solution, what must be done?

Answer 17

As the liquid is highly coloured, readings are normally taken from the top of the meniscus.

Question 18

What is a conical flask designed to do? (2)

Answer 18

It is designed so that it may be swirled without the liquid splashing out of it.
The shape allows any droplets adhering to the inside of it to be easily washed down into the flask.

Question 19

What must be done to the conical flask before being used?

What is important not to do?

Answer 19

It must be washed out with deionised water.

Do not rinse it with the solution it is to contain

Question 20

What colour does methyl orange change from and to when an acidic solution?

Answer 20

yellow to pink

Question 21

What colour does phenolphthalein change from and to when an acidic solution?

Answer 21

pink to colourless