Hi

Chemistry 100 Hour Exam I Name ________________ Show all of your work. Problems without work shown will be graded all -or-nothing. Use the back if necessary. There are 15 questions. Point values are indicated. 1. Classify the following as an element (E), compound (C), homogeneous mixture (HO) or heterogeneous mixture (HE): [10 pts.] a. iron Element b. club soda (cold, with bubbles) Heterogeneous Mixture c. ethanol (C2H6O) Compound d. ice tea (no sugar, no tea leaves visible) Homogeneous Mixture e. white cake frosting Homogeneous Mixture 2. Classify the following as chemical (C) or physical (P) changes: [10 pts.] a. water boils P b. sodium and chlorine react to form sodium chloride C c. a hammer hits a nail P d. bread is burned to become toast C e. hot water and cold water are mixed together P 3. Select the best answer from the ones provided. There is only one best answer. [20 pts.] a. Boron Step Line 1. The line that separates gases from liquids 2. A musical number by the Rockettes 3. The line that separates s electrons from p electrons 4. The line that separates complete shells from incomplete shells 5. None of the above Ans. 5 b. The relationship between wavelength and frequency in a linear wave is: 1. The higher the frequency the shorter the wavelength 2. The lower the frequency the shorter the wavelength 3. The longer the wavelength the higher the frequency 4. Depends on the velocity of the wave 5. None of the above Ans. 1 c. The atomic mass (weight as found on a periodic table) of an element is: 1. The A value 2. The Z value 3. The average A values of isotopes of a given element 4. The average Z values of isotopes of a given element 5. The same as the number of neutrons Ans. 3 d. Hund's Rule states that: 1. Electrons prefer to be spin up 2. Electrons prefer to be unpaired as long as possible in an orbital 3. Only three electrons can be put in an s orbital 4. S electrons have the same shell number as the row number 5. A filled s and p orbital is stable Ans. 2 e. Which data set is an example of precision (the correct measured value is 2) : 1. 1, 2, 3, 4, 5 2. 1.8, 2.5, 1.4, 2.3, 2.0 3. 3.0, 3.0, 3.1, 3.02, 2.9, 3.0 4. 1.8, 2.0, 2.2, 2.4, 2.6 5. None of the above Ans. 3 4. Write the symbol for an element that satisfies the following: [20 pts.] a. A transition metal that starts the letter R ans. Ru, Re, Rh b. An element that is shiny ans. Any metal c. A metalloid that starts with the letter S ans. Si d. An element that has two allotropes skip e. An element with a Z value of 20 ans. Ca 5. Underline which of the following two prefixes is larger. [10 pts.] ans.Skip a. centi or deka b. mega or giga c. kilo or hepto d. giga or nano e. pica or tera 6. How many atoms of each element are present in the following compound [10 pts]: (NH4)3PO2 N =3 H=12 P =1 O =2 7. Using the conversion tables provided, answer the following (show work): [20 pts.] a. Which is smaller, 1.5 x 103 mm or 1.5 x 102 inches? 1.5 x 103 mm = 59.06 inches b. A box has a volume of 10 m3. How many cm3 is the volume of the box (be careful)? 10 m3 = 1 x 107 cm3 c. Which is larger: 2.3 miles or 3.2 km? Explain. 2.3 miles d. Convert 1 decimeter to kilometers (use scientific notation) 1 dm = 1 x 10-4 km e. A man weighs 100 lbs. How many kilograms does he weigh? 100 lbs = 45.45 kg 8. Convert the following temperatures to the indicated units: [20 pts.] 100 oF to K 100 F = 37.7 C = 310.85 K 9. A sample of an unknown element has a density of 8.5 g/cm3. A box made of the element has dimensions 1 cm x 2 cm x 5 cm. What is the mass of the box. If each side of the box is increased ten times (10 cm x 20 cm x 50 cm), does the density change? Explain. [10 pts.] Mass = D x V = 8.5 g/cm3 x 10 cm3 = 85 g. If the box is increased, no change in density because the mass will also increase. 10. Put the following into scientific notation [10 pts.]: a. 3000. ans. 3 x 104 b. .023 x 103 ans. 2.3 x 101 c. .0005 ans. 5 x 10-4 d. 1 micrometer ans. 1 x 10-6 11. Write the detailed, algebraic, valence, and noble gas configurations for the element Ca (Z =20) [20 pts.]. 1s22s22p63s23p64s2 ud ud ududud ud ududud ud (u = up arrow, d = down arrow) 12. Why are copper, silver, and gold used for coinage metals instead of lithium, sodium, and potassium (which are much cheaper to make)? [10 pts.] Ans. They do not react with water 13. An element has 25 protons and 30 neutrons. Write the isotope symbol and identify the element. 55Mn An element has a mass number of 272 and the number of neutrons is 161. Identify the element and write its isotope symbol. [10 total pts.] 272Rg 14. The element gallium has the following % occurrences (mass number) of its stable isotopes: 69Ga = 60.1%, 71Ga =39.9%. Calculate the atomic mass of gallium as found on a typical periodic table. [10 pts.] [(69 x 60.1) + (71 x 39.9)]/100 = 69.798 15. List the electromagnetic spectrum in order from high frequency to low frequency. [10 pts.] Gamma X-ray UV, Visible IR Microwave Radio Answer only one of the following extra credit questions. Extra Credit: Which is larger 31 years or 365 weeks (i. e., a month of years or a year of months)? [10 pts.] [Hint: convert both to days] Extra credit 2: Which has higher density: gold at 200 oF or 1000 oF? Prove your answer. [10 pts.] 1. A. E B. het mix C. Compound D. Homo mix E. homo mix 2. A. P B. c C. P D. C E. c 3. A. 5 B. 1 C. 3 D. 2 E. 3 4. A. Rhodium, rhenium, etc. B.  any metal (iron, etc.) C. Silicon D. Carbon, tin, phosphorus (allotropes are NOT on the exam) E. Calcium 5. Since I will give you the metric chart, this question will not be on the exam.  Scientific notation, instead. 6. N 3 H 12 P 1 O 2 7. A.  1500 mm (.1cm/1mm)(1in/2.54cm) = 59.06in < 150 in B.10m^3 to cm^3 proceed as follows: 10 x 10 ^(m^3 - cm^3) = 10 x 10^(0 --6) = 10 x 10^6 = 1 x 10^7 cm^3