Purpose:

How can we identify a substance created by a chemical reaction?

Procedure:

For this lab, we followed most of the instructions on the lab sheet provided. However, there were a few minor changes. Instead of 25ml we only used 10ml and we used Sodium Carbonate and Strontium Chloride instead of the original Calcium Chloride and Lithium Carbonate. These changes did not affect the lab process, but we used less chemical and chemicals that we had available.

After measuring out 10ml of both Sodium Carbonate and Strontium Chloride, we combined the in one beaker. When combined, the liquids that had previously been clear looked white as thou there was a fine power in it. We poured the new liquid through a piece of filter paper and into a clean beaker. The liquid was then clear, and a white powder had collected in the filter paper.

We already had samples of both the Sodium Carbonate and Strontium Chloride as powder, so we passed both three the flame of a Bunsen burner. The flame was approximately 3cm high, and a clear blue in colour. We got a sample of each powder onto our metal rod with a loop at the end, then passed tit trough the flame. The sodium burned a bright orange, while the strontium was more of a red or pink colour.We did the same test on our mystery powder as well. We discovered that it burned orange, there for was most likely Sodium.

Data & Observations:

Observations

• Properties of reactant A (Sodium Carbonate) :Clear liquid, no colour, no odor, slightly denser than water, room temperature
• Properties of reactant B (Strontium Chloride): Clear liquid, no colour, no odor, room temperature

Observations of changes

• white, liquid, room temperature, mild indistinct odor
• Separated into fine powder and clear liquid. Liquid matched both reactant A and B.

Flame test results

• Reference ion 1 (Sodium): Burned a bright orange, White powder, fine, room temperature, solid, no distinct odor.
• Reference ion 2 (strontium): Burned a red/pink, White powder, fine, room temperature, solid, no distinct odor.
• Unknown solid (product of reaction): Burned a bright orange, White powder, fine, room temperature, solid, no distinct odor, slightly wet from separation from liquid.

Analysis:

There are two possible option for what the powder and liquid are. Mixing Sodium Carbonate and Strontium Chloride could have created either Strontium carbonate or sodium chloride. (SrCO₃ or NaCl)

Conclusion:

The flame test showed that the mystery powder burned white, like sodium therefor the powder must be sodium as well. Form this, we can decide that the Mystery liquid and powder (Which we obtained by mixing Sodium Carbonate and Strontium Chloride), was Sodium chloride. Had the powder been strontium, it would have burned red. This method of identification is not always exact, but it can give a good idea of the contents of a compound.

Please click on this to see the Photos. Sorry, I was unable to insert them directly into my post.