CHEM 112L Review Questions on Anion and Salt Qualitative Analysis, Molar Mass by Freezing Point Depression PDF

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CHEM 112L Review Questions on Anion and Salt Qualitative Analysis, Molar Mass from Freezing Point Depression General areas to understand a. Anion qualitative analysis: Understand and be able to apply the logic of how to differentiate among anions based upon their patterns of reactivity in the series...

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CHEM 112L Review Questions on Anion and Salt Qualitative Analysis, Molar Mass from Freezing Point Depression 1. General areas to understand a. Anion qualitative analysis: Understand and be able to apply the logic of how to differentiate among anions based upon their patterns of reactivity in the series of tests you performed. b. Salt qualitative analysis: Given cation and anion test results and a table of reactivity of anions in the tests, be able to i. Identify the anion and cation in an unknown salt. ii. Write the correct formula for this salt. c. Molar mass by freezing point depression. (experiment performed 3/6 and 3/7/19) i. Given experimental data like that you obtained in lab, be able to calculate the molar mass of a non-dissociating solute. 1. Know the equation ΔTf = kfm. 2. Know the definition of molality, m. 3. Know the definition of molar mass. 4. You will be furnished the value of kf for water, the solvent we are using. ii. Describe and explain the effect of solute dissociation on calculated molar mass vs. actual molar mass, e.g., for NaCl vs. a nonionizing (molecular) solute. 2. Sample questions regarding qualitative analysis of anions and salts a. No reaction occurs when you perform all the anion reactivity tests (H2SO4, AgNO3, HNO3, barium acetate, and HCl). What can you conclude and what do you do next? Explain. b. All nitrates are soluble. What is it about HNO3 that enables this reagent to differentiate among the precipitates formed by different anions reacting with AgCl? c. No reaction occurs when you add HCl to an aqueous solution of your salt unknown. What can you conclude from this outcome? d. Your salt unknown is a colorless, granular solid. When dissolved in water it does not form a colored solution with ammonia under basic (alkaline) conditions. What cations can you conclude definitely are not present? e. A solution of your salt unknown reacts with KSCN to form a deep red color which remains in solution. What ion is indicated by this result?...