10 Unknowns Chem II
Purpose: The purpose of this experiment was to be able to apply our knowledge of chemistry to identify 10 unknown elements that were presented to us. We were allowed to use Bunsen burners, hydrochloric acid, use PH paper to test if the unknown solution is an acid or a base, and precipitate each unknown solution with each other.
Procedure / Data / Conclusions:
Unknown #1: I found solution 1 to be KI. While doing the precipitate reactions, I found that it precipitates only with BiCl3 to form BiI3 which is an inorganic compound. The precipitate reaction is shown below: 3KI(aq) + BiCl3(aq) ⇒ 3KCl(aq) + BiI3(s)
Since potassium is very soluble and bismuth reacts with iodine, I concluded that solution 1 is KI.
Unknown #2: I found solutions #2 to be H2SO4. While doing precipitate reactions for solution #2, I found that it fizzed with two other solutions; #6 and #8. This led me to believe that since there were two carbonates in our list of solutions, solutions 6 and 8 were the carbonate solutions. This was also one of the last three solutions that I found the name of. H2SO4 is a strong base, and a PH test revealed that it had a very low PH of 1. Also already knowing that solution 6 was NaHCO3 and solution 8 was Na2CO3, I was also able to confirm solution 2 was NaOH by the following reactions:
H2SO4(aq) + 2 NaHCO3(aq) ⇒ Na2SO4(aq) + 2 CO2(g) + 2 H2O(l)
H2SO4(aq) + Na2CO3(aq) ⇒ Na2SO4(aq) + CO2(g) + H2O(l)
These reactions show that the fizzing that occurred while performing precipitate reactions was the release of CO2 gas. All findings lead to the fact that unknown solution #2 is H2SO4.
Unknown #3: Solution 3 is Na2SO4. While doing the precipitate reactions, I found that solution 3 only precipitated with solution 9 (BaCl2). The precipitate can be seen in the double replacement reaction below: Na2SO4(aq) + BaCl2(aq) ⇒ 2NaCl(aq) + BaSO4(s)
The solid was formed with barium and sulfate.
Procedure / Data / Conclusions:
Unknown #1: I found solution 1 to be KI. While doing the precipitate reactions, I found that it precipitates only with BiCl3 to form BiI3 which is an inorganic compound. The precipitate reaction is shown below: 3KI(aq) + BiCl3(aq) ⇒ 3KCl(aq) + BiI3(s)
Since potassium is very soluble and bismuth reacts with iodine, I concluded that solution 1 is KI.
Unknown #2: I found solutions #2 to be H2SO4. While doing precipitate reactions for solution #2, I found that it fizzed with two other solutions; #6 and #8. This led me to believe that since there were two carbonates in our list of solutions, solutions 6 and 8 were the carbonate solutions. This was also one of the last three solutions that I found the name of. H2SO4 is a strong base, and a PH test revealed that it had a very low PH of 1. Also already knowing that solution 6 was NaHCO3 and solution 8 was Na2CO3, I was also able to confirm solution 2 was NaOH by the following reactions:
H2SO4(aq) + 2 NaHCO3(aq) ⇒ Na2SO4(aq) + 2 CO2(g) + 2 H2O(l)
H2SO4(aq) + Na2CO3(aq) ⇒ Na2SO4(aq) + CO2(g) + H2O(l)
These reactions show that the fizzing that occurred while performing precipitate reactions was the release of CO2 gas. All findings lead to the fact that unknown solution #2 is H2SO4.
Unknown #3: Solution 3 is Na2SO4. While doing the precipitate reactions, I found that solution 3 only precipitated with solution 9 (BaCl2). The precipitate can be seen in the double replacement reaction below: Na2SO4(aq) + BaCl2(aq) ⇒ 2NaCl(aq) + BaSO4(s)
The solid was formed with barium and sulfate.