First Term Review

Instructions: Answer the following questions. Type your answers except for the mathematical problems (those should be done by hand). Some of the questions will be counted toward extra points for other assignments but you should answer all questions. Review is due on Friday September 2nd, 2011.

1. Define the following words if pertainable give examples: Chemistry Matter Substance Sustainability Mass Weight Model Atomic level Energy Elements Compounds Homogenous mixtures Heterogeneous mixture Electron Proton Neutron Subatomic particles Nuclide symbol and its parts 2. What are CFC’s? How do they affect our environment? 3. Give three examples of SI units and what they measure. 4. What are prefixes used for? 5. Describe three phase changes and where they can occur.

6. What’s the difference between intensive and extensive properties? Exemplify your answer. 7. Do chemical reactions affect our environment? How? Give specific examples. 8. What law does the following scenario describe? One gram of Sodium Chloride always contains 0.3934 grams of Sodium and 0.6066 grams of Chlorine. 9. Describe the following as a cation, anion, or polyatomic ion. Ni2+ Te2- NH4+ N3- Rb+ HPO4

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10. How are isotopes differentiated? 11. Make a time line of the evolution of the atomic theory (write scientist names and their experiments). 12. What information about an element can you find in the periodic table? 13. Write the formula for the following ionic compounds: Fe2+ PO4

3- Iron (II) Phosphate Fe3(PO4)2 Ti4+ O2- Titanium (IV) Oxide Ti2O4 Mg2+ Br- Magnesium Bromide MgBr2

14. Using the following data, calculate the average atomic mass of an unknown element and determine what element it is: Mass number Isotopic Mass (amu) Fractional Abundance 50 49.9461 0.0435 52 51.9405 0.8379 53 52.9407 0.0950 54 53.9389 0.0236 Average Atomic Mass = (49.9461)(0.0435) + (51.9405)(0.8379) + (52.9407)(0.0950) + (53.9389)(0.0236) Average Atomic Mass = 51.9956 amu Chromium 15. Two samples of different compounds of nitrogen and oxygen have the following composition. What are the two compounds? What law can you use to solve this problem? Amount N Amount O Mass ratio (O g/N g) Comp A 1.206 g 2.755 g 2.755/1.206 = 2.2844 Comp B 1.651 g 4.714 g 4.714/1.651 = 2.8551 Whole Small Number Ratio = 2.2844/2.8551 = 1.2499 = 1.25 = 5/4 Compound A – NO4 Compound B – NO5 16. What is the mass percent of carbon in CH2O? Mass percent = mass of element / total mass * 100 Mass percent = 12.011g/mol / (12.011 + 2*1.01 + 15.999) g/mol * 100 Mass percent = 39.997 % 17. The world’s oceans contain approximately 1.35 x 109 km3. What is the volume in liters? 1.35 x 109 km3 (1000 m)3 (10 dm)3 1 L = 1.35 x1021 L (1 km)3 (1 m)3 1 dm3 18. A sample of nitrogen gas in a glass bulb weighs 243 mg. What is this mass in SI base units of mass? 243 mg 1 g 1 kg = 2.43 x10-4 kg 1000 mg 1000 g

19. Identify a substance that when poured into a graduated cylinder the volume is 35.1 mL and has a mass of 30.5 g. Substance Density (g/mL) n- butyl alcohol 0.810 ethylene glycol 1.114 isopropyl alcohol 0.785 toluene 0.866

1. Find the density of the substance you have: D = 30.5 g / 35.1 mL = 0.869g/mL

2. Compare it to the given chart: Toluene 20. Write the following in terms of the SI base unit (write them in scientific notation) a. 1.07 ps b. 5.8 micrometer c. 19.6 ms d. 15.3 ms a) Base unit for time: seconds 1.07 ps 1 s = 1.07x10-12 s 1x1012 ps b) Base unit for length: meter 5.8 micrometers 1 meter = 5.8x10-6 meters 1x106 micrometers c) Base unit for time: seconds 19.6 ms 1 s = 1.96x10-2 s 1000 ms d) Base unit for time: seconds 15.3 ms 1 s = 1.53x10-2 s 1000 ms 21. Tungsten metal, which is used in light bulb filaments, has the highest melting point of any metal (3410oC). What is the melting point in degrees Fahrenheit? F = 1.8C + 32 à F = 1.8(3410) + 32 = 6170 F 22. How many atoms of Pd are in 3 grams of Palladium? (Hint: use average atomic mass in amu or g/mol and Avogadro’s number). 1. Find the average atomic mass of Palladium: 106.42 g/mol 3 g mol 6.023x1023atoms= 1.698x1022 atoms 106.42 g mol

23. What element do I have in a sample with a mass of 3 grams and about 2.287x1022 atoms. 1. In order to identify the element you need to find its average atomic mass. 3 g 6.023x1023 atoms = 79.007 g/mol 2.287x1022 atoms mol 24. What do Pauli’s exclusion principle and Hund’s rule state? 25. Give the electric configuration of the following elements. Ca I Mg N Al