Moles 2

Question 1

How to calculate percentage by mass

Answer 1

%x = mass of x / RFM x100

Question 2

How to calculate moles (with mass and rfm)

Answer 2

Moles = mass (g)/RFM

Question 3

How to calculate mols

Answer 3

no of mol = vol(dm3) / 24
no of mol = vol(cm3) / 24000

Question 4

What is the equation linking concentration (mol/dm3), number of moles, and volume (dm3).

Answer 4

C = n / v

Question 5

What two special pieces of equipment do you need to do titration? I

Answer 5

Volumetric pipette
Burette

Question 6

Describe the set up of a titration experiment.

Answer 6

1. Use a volumetric pipette to place 25cm3 of the unknown alkali into a conical flask
2. Add a few drops of methyl orange or phenolphthalein indicator to the flask
3. Fill a burette with known acid and clamp it above the conical flask

Question 7

Describe the usage of the titration set up.

Answer 7

Measure the initial volume of the acid on burette
Use the burette to add acid into the conical flask drop by drop and swirling the flask
Close the burette as soon as the colour changes
Measure the final volume of acid
Calculate titre
Repeat to get concordant (within 0.2cm3)

Question 8

What is a concordant result?

Answer 8

results within 0.2cm3 of each other