PSU Chem 111 Lab Final Exam with Guaranteed Pass Solutions Updated.

Spectroscopy - Answer The study of the interaction of electromagnetic radiation with matter Calorimetry - Answer Determining the changes in energy of a system by measuring the heat exchanged within the surroundings What is "alum"? - Answer A double salt combination of aluminum and a group 1A or ammonium sulfate Give two reasons why aluminum is expensive to produce and two uses for the alum compound that you synthesized. - Answer 1) It requires a lot of energy to produce & most aluminum mines are out of US so you have to import it 2) paper making & soap Explain the difference between corrosion of iron and corrosion of aluminum - Answer Iron reacts with oxygen and breaks down, while aluminum forms a thin film to protect itself You used two different types of indicators in this experiment - red cabbage extract and bromothymol blue (BTB). Be able to cite one advantage of the BTB indicator over red cabbage extract - Answer BTB is synthetically made, and more pure, also can be produced whenever needed Explain the difference between a "serial" titration and a "single well" titration. - Answer Serial -using mulitple wells to determine when the color changes (Advantage: each step seen) Single Well - uses single well to determine pH (Advantage: uses less chemicals) Explain what is meant by a "back titration." Why is this a better approach than a regular titration for the analysis of calcium carbonate in egg shells. - Answer An excess of HCl is added to dissolve the calcium carbonate, then the unreacted acid is titrated with a soluble base to make the standard solution; it is faster & easier to determine the end point What are the advantages and disadvantages of lithium hydroxide and activated carbon as CO2 scrubbers? - Answer Disadvantages of Lithium - not cost effective Advantages of Lithium - filters more than activated carbon Advantages of activated carbon - you can use it more than once & has large surface area