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Lecture 2

# Lecture 2 - Chapter 1 Measurements 11 Units of Measure SI...

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Unformatted text preview: Chapter 1. Measurements 11. Units of Measure: SI Units *Systme International d'Units ( = "International System of Units"), 11th General Conference on Weights and Measures (1960) Fundamental Units Fundamental Units Quantity Unit Length meter (M) Mass kilogram (kg) g ( g) Time second (s) Temperature kelvin (K) Amount of Substance mole (mol) Electric Current ampere (A) Luminous Intensity candela (cd) Plant angle radian (rad) Solid angle steradian ( ) S lid l di (sr) As a scientist, you need to remember these units ! Derived Units Quantity Frequency Frequency Force Pressure Energy/Work/Heat gy/ / Power Electric Charge Electric Potential Electrical Resistance Electrical Capacitance Radioactivity Unit hertz (Hz) 1/s hertz (Hz) 1/s newton (N) m kg/s2 pascal (Pa) N/m2 j joule (J) () N m watt (W) J/s coulomb (C) s A volt (V) W/A ohm () V/A farad (F) C/V becquerel (Bq) 1/s As a scientist, you need remember these units ! Accepted NonSI Units Quantity Volume Length Time Unit liter (L) ( ) 103 m3 (dm3) ( millilter (mL) 106 m3 (cm3) angstrom () 1010 m minute (min) 60 s hour (h) 60 min = 3600 s day (d) 24 h = 86,400 s metric ton (t) 103 kg gram 103 k 0 3 kg electron volt (eV) 1.60217653 x 1019 J bar (bar) 105 Pa atmosphere (atm) 101,325 Pa atmosphere (atm) 101 325 Pa torr (= 1 mmHg) 133.322 Pa pound/in2 (psi) 6,894.76 Pa Mass Energy Pressure As a scientist, you need to remember these units ! Other Units Quantity Unit Length inch (in.) Mass pound (lb) Energy calorie (cal) (cal) Calorie (C) Temperature centigrade/Celsius (C) Fahrenheit (F) F h h i (F) 0.0254 m 0.45359237 kg 4.184 J 4 184 J 4.184 x 103 J K273.15 1.8 (K273.15)+32 1 8 (K 273 15) 32 As a scientist, you need to remember these units ! Prefixes as Multipliers yotta Y 1024 zetta Z 1021 exa E 1018 peta P P 1015 0 tera T 1012 giga G 109 mega M 10 mega M 106 kilo K 103 Hecto H 102 deca da 101 deci d 101 centi c 102 milli m 103 micro micro 106 0 nano n 109 pico p 1012 femto f 1015 femto f 10 15 atto a 1018 zepto z 1021 yocto y 1024 As a student, you need to remember the prefixes in the two boxes! Converting Between Unites Example: A 100pound woman working as a secretary consumes about Example: A 100 pound woman working as a secretary consumes about 1000 kcal per working day. Her works eight hours a day. (1) Express this number in joules per second per kilogram of body weight (1) Express this number in joules per second per kilogram of body weight (watts per kilogram). (2) Which consumes more energy, the secretary or a 100W light bulb. 12. Chemical concentrations Concepts: 1. Solution: 2. Solvent: 3. Solute: 4. C Concentration: i 5. Mole: 6. Atomic mass: 7. Molecular mass: 12. Chemical concentrations 8. Molarity (M): 9. Electrolyte: strong and weak 10. Formal concentration (F): 11. Molality: Example: typical seawater contains 2.7 g of NaCl (sodium Example: typical seawater contains 2.7 g of NaCl (sodium chloride) per 100 mL. (a) What is the molarity, formal concentration, and molality of NaCl in the ocean. (b) MgCl has a concentration of 0.054 M in the ocean. (b) MgCl2 has a concentration of 0 054 M in the ocean How many grams of MgCl2 in a liter of seawater? 12: weigh percent 13: volume percent Example: Find the molarity and molality of of 37.0 wt% HCl aqueous solutions. q 14: Part per Million (ppm) and Parts per Billion (ppb) p (pp ) p (pp ) Find the molarity of NaCl of 1 ppm in water. Find how many liters of CO in a liter of air when the concentration of CO is 10 ppb. 13. Preparing solutions: 1 3 Preparing solutions: (1) Preparing a solution with a desired molarity: Preparing a solution with a desired molarity: How many grams of CdCl2 should be dissolved in a volume of 50.0 mL to 1.00 mM Cd2+? (2) Dilution: How many mililiters of 37.0 wt% HCl should be diluted to make 0.100 M HCl? 14 Stoichiometry 14 Stoichiometry calculations Concept: Gravimetric Analysis Gravimetric Analysis If each tablet provides 15 mg of ion. How many tablets should Analyze to provide 0.50 g of Fe Analyze to provide 0 50 g of Fe2O3 products? products? Home Work of Chapter 1: H W k f Ch 1 Ideally, you should work on all the problems in the end of Chapter 2. But following problems are relative more important: 1 5, 1 7, 1 11, 1 12; 1 15, 1 20; 1 25; 1 32; and 1 35 15 17 111 112; 115 120; 125; 132; and 135 ...
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