Unknown compound Lab Report Example | Topics and Well Written Essays - 2500 words

Unknown compound - Lab Report Example In this experiment, the flame test of the unknown solution gave a pink color indicating presence of potassium ions. The chemical reaction between the unknown solution and barium chloride followed by acidification using dilute nitric acid gave a white precipitate indicating presence of sulfate ions, which resulted from formation of barium sulfate that is an insoluble salt. The pH and conductometry tests gave numerical values of 7.90 and 3.031Ãâ€"10^4  µS/cm, respectively. The unknown solution had a pH similar to that of the known while the conductivity value of the unknown was different from that of the known by a small margin (-0.003Ãâ€"10^4  µS/cm). Synthesis of potassium sulfate from a reaction between potassium hydroxide and dilute sulfuric acid gave a percentage yield of 89.70%. Following the results obtained in this experiment, the identity of the unknown was confirmed to be potassium sulfate. Physical and chemical characteristics can be used to determine the identity of an unknown compound. Physical properties are those that can be determined without changing the composition of the substance. These include color, taste, odor, melting and boiling point, conductivity and density of a substance. Qualitative analysis is the process of determining the composition of chemical substance in matter by conducting various chemical tests (Davis et al., 2005). Most aqueous samples of various salts can be tested for characteristic reactions by reacting them with dilute nitric acid, dilute hydrochloric acid, aqueous barium nitrate/chloride, silver nitrate, ammonium hydroxide or sodium hydroxide. These reagents are used in determining presence of anions (negatively charged particles) in unknown samples, which must be in aqueous states before the tests can be conducted. A number of signs can be used to deduce whether a chemical reaction has taken place some of which include: Color changes, formation of a precipitate (a solid product which ‘falls out