Discussion There were four goals for Project 11: Identification, Properties, and Synthesis of an Unknown Ionic Compound. The first goal was to identify the unknown compound, the second goal was to determine the reactivity of the compound, the third goal was to determine the quantitative solubility of the compound in water, and the fourth goal was to find the percent yield of a product from a reaction involving the unknown compound.
Determining the identity of the unknown compound was achieved by performing a variety of tests for the physical properties of the substance. Some of these properties, such as melting point and chemical structure, could be discovered by making a few immediate observations of the substance. The unknown compound …show more content…
By combining the unknown compound with an acid, a base, and two salts, its reactivity was determined. Reacting the unknown compound with sulfuric acid (H2SO4) produced no visible reaction (precipitate), although the pH of the resulting solution was very acidic. Combining the unknown compound with sodium hydroxide (NaOH), a strong base, also had no visible reaction. However, the resulting solution was a lot more basic. Reacting the unknown compound with sodium nitrate (NaNO3), a salt, did not have a visible reaction nor did the pH of the resulting solution change. The last reaction involved the unknown compound and silver nitrate (Ag(NO3)2), another salt. A milky, white precipitate was produced (AgCl2) and there was no change in pH. After performing these reactions, it was apparent that our unknown compound (KCl) was not very reactive. There were some conclusions about its reactivity that we could make from the results. When the unknown compound is combined with a strong acid or base, there tends to not be a visible reaction, probably because the products are soluble. The resulting solution when the unknown compound was reacted with a strong acid had a very low pH value, meaning that it became very acidic. The pH value of the resulting solution when the unknown compound was reacted with a strong base was very high, meaning it was very basic. …show more content…
When calculating the quantitative solubility of the unknown compound in water, the amount of water that was measured in the hydrated cylinder and poured into the flask could have been greater than expected. This is more likely than less water being used because more solute was needed to saturate the solution than expected. Another error that could have occurred during this part of the experiment was that too much of the unknown compound was added accidently to the solution than could dissolve. Most of the error in this lab occurred during the quantitative analysis since all of the percent yields of the precipitate were over 100%. This miscalculation could have been caused by the beakers not being washed out thoroughly between each reaction or by the mass of KCl measured on the electronic scale being greater than exactly 0.5 grams. However, the most likely cause is that not enough time was allowed for the water to evaporate from the precipitate in the oven before it was measured on the scale. More effort should have been taken to make sure that these errors did not
Determining the identity of the unknown compound was achieved by performing a variety of tests for the physical properties of the substance. Some of these properties, such as melting point and chemical structure, could be discovered by making a few immediate observations of the substance. The unknown compound …show more content…
By combining the unknown compound with an acid, a base, and two salts, its reactivity was determined. Reacting the unknown compound with sulfuric acid (H2SO4) produced no visible reaction (precipitate), although the pH of the resulting solution was very acidic. Combining the unknown compound with sodium hydroxide (NaOH), a strong base, also had no visible reaction. However, the resulting solution was a lot more basic. Reacting the unknown compound with sodium nitrate (NaNO3), a salt, did not have a visible reaction nor did the pH of the resulting solution change. The last reaction involved the unknown compound and silver nitrate (Ag(NO3)2), another salt. A milky, white precipitate was produced (AgCl2) and there was no change in pH. After performing these reactions, it was apparent that our unknown compound (KCl) was not very reactive. There were some conclusions about its reactivity that we could make from the results. When the unknown compound is combined with a strong acid or base, there tends to not be a visible reaction, probably because the products are soluble. The resulting solution when the unknown compound was reacted with a strong acid had a very low pH value, meaning that it became very acidic. The pH value of the resulting solution when the unknown compound was reacted with a strong base was very high, meaning it was very basic. …show more content…
When calculating the quantitative solubility of the unknown compound in water, the amount of water that was measured in the hydrated cylinder and poured into the flask could have been greater than expected. This is more likely than less water being used because more solute was needed to saturate the solution than expected. Another error that could have occurred during this part of the experiment was that too much of the unknown compound was added accidently to the solution than could dissolve. Most of the error in this lab occurred during the quantitative analysis since all of the percent yields of the precipitate were over 100%. This miscalculation could have been caused by the beakers not being washed out thoroughly between each reaction or by the mass of KCl measured on the electronic scale being greater than exactly 0.5 grams. However, the most likely cause is that not enough time was allowed for the water to evaporate from the precipitate in the oven before it was measured on the scale. More effort should have been taken to make sure that these errors did not