Standard solution

Question 1

1.

Answer 1

weigh solid into sample tube

then tip –> beaker and reweigh

Question 2

2.

Answer 2

dissolve solute in a small amount of solvent - warm if necessary

Question 3

3.

Answer 3

transfer the solution into volumetric flask

The solution is poured down a glass rod as the liquids are transferred from the beaker –> graduated flask
to prevent drips of solution running down side of beaker, thus ensuring all the KHP in solution is transferred to the graduated flask

Question 4

4.

Answer 4

rinse all the solution from the beaker using a wash bottle into the flask - using more solvent

Question 5

5.

Answer 5

carefully make up the solution to the mark using a pipette

Question 6

6.

Answer 6

stopper and mix well

Question 7

what is a standard solution?

Answer 7

a solution with accurately known concentration

Question 8

what constitues a primary standard

Answer 8

a chemical which can be weighed out accurately to make up a standard solution

is very pure
does not gain or lose mass in air
has a relatively high molar mass so weighing errors minimised

Question 9

suggest a reason why anhydrous sodium carbonate can be used as a primary standard but hydrated not?

Answer 9

hydrated sodium carbonate gradually loses water, therefore a sample of this solid does not have a definite composition
anhydrous sodium carbonate can be heated strongly to drive off any water - stbale compound does not decompose on heating