Unit Three, Chapter Thirty Four - Standard solutions and dilutions

Question 1

What is a standard solution?

Answer 1

A solution where the concentration is known accurately

Question 2

What are the properties of a primary standard?

Answer 2

(1) High purity
(2) Stable in air and in solution
(3) Readily soluble in solvent
(4) High enough solubility that solutions of relatively high concentration can be prepared
(5) Reasonably large relative formula mass in order to minimise uncertainty in the mass of substance weighed out

Question 3

What apparatus is used in dilution?

Answer 3

Standard flasks

Question 4

Stages of dilution

Answer 4

(1) Pipette a known volume of standard solution into a clean standard flask
(2) Add deionised water to the flask until the water is just below the graduation mark
(3) Use a dropper to add deionised water until the bottom of the meniscus is on the graduation mark
(4)Put stopper in standard flask then invert to mix thoroughly

Question 5

What is the dilution factor?

Answer 5

The amount the original solution is diluted by

Question 6

dilution factor =

Answer 6

total volume after dilution/initial volume added

Question 7

How to convert from mol l^-1 to g l^-1

Answer 7

Multiply by GFM

Question 8

How to convert from g l^-1 to mol l^-1

Answer 8

Divide by GFM