Name ________________________________          Gen Chem I Lecture Exam 1            4567 19SEP20024567       Dr. L. J. Rivela

1. YOU MUST SHOW ALL EQUATIONS, LOGIC, AND CALCULATIONS IN ORDER TO                                                                 RECEIVE ANY CREDIT ! 2. ALL NUMERICAL ANSWERS MUST HAVE THE PROPER NUMBER OF SIGNIFICANT FIGURES AND BE EXPRESSED IN SCIENTIFIC NOTATION WHERE NECESSARY.

1.       YOU MUST SHOW ALL EQUATIONS, LOGIC, AND CALCULATIONS IN ORDER TO                                      RECEIVE ANY CREDIT ! 2.     ALL NUMERICAL ANSWERS MUST HAVE THE PROPER NUMBER OF SIGNIFICANT         FIGURES AND BE EXPRESSED IN SCIENTIFIC NOTATION WHERE NECESSARY.

1. Please supply the basic "S I" units [spell the term: ex second not s]  [12]       PHYSICAL QUANTITY               SYMBOL OF UNIT IN BASIC SI                                           time                                                     second

2. Please supply the correct name or symbol. Proper spelling is essential.         [a] G e                                         [d] Si                                         [12]   [b] V                                            [e] B e                                              [c] Mn                                          [f] F

3. Indicate the proper number of significant figures in each of the following numbers      or in the result of the indicated calculation [do NOT give the result of the calculation]: [10]       [a] 382.703                                                [d] (56.489 + 6.2)                                [b] 0.0000835                                            [e] (56.489 ÷ 6.2)                               [c] 1200.0 x 10exp4

4. Perform the following calculations. Please express your answers in scientific notation.                   [9352.4x10exp-34] [37.36x10exp234] [a]                                                                             =                                 4.78x10exp-126 [8]                         [9.58x10exp6 - 88x10exp5]                 = [b]                               5.802x10exp-23

5. Consider the following        Temperature               KBr                     KI                solubilities:                              95°C          50.0 g/100g H2O     200. g/100g H2O                                                  10°C           10.0 g/100g H2O     125 g/100g H2O      Given a sample which contains 250. g of KBr and 470. g of KI . . . . . .      [a] Define solubility [18]     [b] calculate the percent KI in the sample. . . . % KI          [c] Suppose that the sample is totally dissolved in 600. g of H2O @ 95°C and then the           resulting solution was cooled to 10°C. Calculate the quantities of KBr and KI that will           crystallize from the solution.               g KBr               g KI

6. Please define 3 [THREE] of the following terms in SHORT, CONCISE STATEMENTS.      Draw a line through the term not defined and please write clearly.             If you do not omit one of the FOUR, only the first THREE will be graded!         [1] CHEMISTRY [9]     [2] FRACTIONAL DISTILLATION         [3] HETEROGENEOUS MIXTURE         [4] WORK

7. When the Pharmacopoeia of London was compiled in 1618, the troy system of      measure was used to prepare medicine. Among the units used were :             20 grains = 1 scruple; 3 scruples = 1 drachm [10]       12 ounces = 1 pound ; 8 drachms = 1 ounce      On the basis of these conversions, please determine how many grains are contained in      8.63 pounds.

8. Consider a solid object which has a volume of 1.4239 liters and a known density of      5.98x10exp3  lb./qt. What is the mass of this object in grams?   [10]

9. Some magnesium wire weighing 2.4 grams is placed in a beaker and covered with 15.0      grams of dilute hydrochloric acid. The acid reacts with the metal and gives off hydrogen [8]      gas, which escapes into the surrounding air. After reaction, the contents of the beaker weigh      17.2 grams. What is the mass of the hydrogen gas produced by this reaction ?            g H2          Explain clearly the logic and "law" involved in determining your response.

10. Please calculate the numerical value at which the Celsius and Fahrenheit temperatures           scales have the same value [ i.e. are equal ] [10]

11.                  M   A   T   C   H   I   N   G:        (a) Choice items [A to U] may be used ONCE, MORE THAN ONCE, OR NOT AT ALL!          [13]  (b) Note: there may be more than one answer to a given question.        (c) Place the appropriate letter (s) in the spaces provided.                 [1] extrinsic property                [2] solution                 [3] gas in equilibrium with solid                [4] intrinsic property                 [5] H2O (g) Æ H2O (l)                                           [A] area                    [H] deposition                   [O] oxidation                                         [B] the atmosphere     [I] homogeneous mixture     [P] peanut butter         [C] boiling point         [J] ionization                    [Q] phase transition                                 [D] bubble gum         [K] length                        [R] potassium                                         [E] cathode ray          [L] liquefaction                 [S] reduction         [F] condensation        [M] mass                          [T] salt and water         [G] density                [N] organic                      [U] sublimation

Extra credit . . . if you like           An average human male breathes about 8.50 x10exp3 L of air per day. The           concentration of lead [Pb] in highly polluted urban air is 7.0 x 10exp-6 g Pb / m3 . [12]     Assume that 75% of the lead particles in the air are less than 1.0 x 10exp -6 m in           diameter, and that 50% of the particles below that size are retained in the lungs.           Calculate the mass of lead  absorbed in this manner in one year by an average male           living in this environment.