LAB ACT 1

Question 1

Describe your observations

Answer 1

orange-brown precipitates

Question 2

Give the balanced chemical equation for this reaction.

Answer 2

3NaOH (l) + FeCl3 (l) → Fe(OH)3 (s) + 3NaCl (aq)

Question 3

What is the name of the precipitate that was formed?

Answer 3

Ferric Hydroxide

Question 4

What is the name of the supernatant liquid?

Answer 4

Sodium Choride

Question 5

What is the purpose of placing an equal volume of water?

Answer 5

prevent it
from being thrown up during centrifugation

Question 6

Describe the result after centrifugation.

Answer 6

precipitates or solids separated from the liquid portion and got
compacted at the bottom of the centrifuge tube.

Question 7

What is the function of the centrifuge?

Answer 7

separate the particles (precipitate)
suspended in a liquid according to particle size and density, viscosity
of the medium, and rotor speed. gravitational force
will cause the particles of higher density than the solvent to sink, and
those less dense than the solvent to float to the top

Question 8

What proper precaution is needed in removing the liquid portion?

Answer 8

Care and particular thoroughness must be applied so as not to
disturb the precipitates or remove some of it during the extraction or
decantation of the supernatant liquid.

Question 9

These ions may cause interference in the analysis of the precipitate and are usually
removed by:

Answer 9

Washing of the Precipitate

Question 10

What is the purpose of washing the precipitate?

Answer 10

To remove interfering ions or chemical reagents that may
contaminate the subsequent tests

Question 11

Heating in a Water Bath
Describe the results: