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General Chemistry

Study the properties, composition & changes of matter. Chemistry is essential for economies & major scientific fields. Learn about observation, conclusions, and the scientific method.

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General Chemistry

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  1. General Chemistry M. R. Naimi-Jamal Faculty of Chemistry Iran University of Science & Technology

  2. محمد رضا نعیمی‌ جمال • شیمی‌ آلی • ساعت رفع اشکال : شنبه ها و دوشنبه ها ۱1-۱0 • مکان: طبقه اول دانشکده شیمی، اتاق 115 • naimi@iust.ac.irE-mail:

  3. ارزشیابی • امتحان میان ترم 8 نمره4۰% • امتحان پایان ترم۱۲ نمره ۶۰% • کار کلاسی و تمرین 1 نمره- غیبت مجاز: ۳/۱۷کل ساعت درسی

  4. فصل اول: مفاهیم اساسی‌

  5. CHEMISTRY: Chemistry is the study of the properties, composition, and structure of matter, the physical and chemical changes it undergoes, and the energy liberated or absorbed during those changes.

  6. Why Study Chemistry? • 1. To better understand the world: what it is made of and how it works. • 2. Because it is the most practical and relevant of the sciences - chemistry is the study of EVERYTHING! • 3. It is the “Central Science” - All other sciences intersect at and depend on chemistry. • It is essential to the national and local economies. • It is required for virtually every major involving Science, mathematics, or engineering. • And what reasons can you think of ?

  7. Chemistry is an Observational Science • Observation: Using the five senses to “see” what is and happens around you. • Conclusion: An explanation of the cause or causes for one or more observations.

  8. Observations vs. Conclusions OBSERVATION: • When electricity is passed through a salt solution, a yellow-green gas and a colorless, flammable gas forms. CONCLUSION: • The yellow-green gas is chlorine and the colorless gas is hydrogen.

  9. The Scientific Method 1. Collect Facts or Data (Observe!!) 2. Search for Generalizations or Laws to Summarize the Facts. 3. Freely Use Your Imagination to Construct Theories or Models of Nature that Will Account for the Laws. 4. Test Theories/Hypotheses for Accuracy. 5. Modify Theories/Hypotheses as Necessary Based on Your Test Results.

  10. فهرست • ماده و انرژی • واحد های بین المللی ‌SI • عدم قطعیت و ارقام معنی‌ دار • آنالیز ابعادی

  11. کائنات ماده انرژی

  12. طبقه بندی کائنات ماده (Matter):فضا اشغال می‌ کند، جرم و اینرسی‌ دارد انرژی (Energy): توانایی انجام کار یا تولید حرارت

  13. ماده وانرژی رابطه اینشتین E = mc2 جرم – انرژی

  14. The Law of Conservation of Matter: Matter is neither created nor destroyed during a chemical reaction or a physical change. The Law of Conservation of Energy: Energy is neither created nor destroyed during a chemical reaction or a physical change. It can only be changed from one form into another. The Law of Conservation of Matter/Energy: The combined amount of matter and energy in the universe is constant. E = mc2

  15. حالات ماده گاز مایع جامد

  16. حالات ماده Solid: has a rigid shape and a fixed volume that changes very little with temperature and pressure Liquid: like solids have a fixed volume but no definite shape (take on the shape of the container) Gas: no fixed volume - volume determined by the size of the container - the volume of a gas varies greatly with temperature and pressure

  17. طبقه بندی مواد

  18. طبقه بندی مواد • Substance :(ماده خالص) A distinct type of matter. Allsamples of asubstance have the same properties. Elements and compounds are substances. • Mixture :(مخلوط) A sample of matter consisting oftwo or more substances which are NOTchemically combined.

  19. Classification of Matter (Substances) Substances: • Element: A substance that cannot be broken down (decomposed) into simpler substances by chemical reactions, e.g.: iron, gold, oxygen. • Compound: A substance composed of two or more elements chemically combined in fixed ratios by mass. Water - H2O Carbon dioxide - CO2 Sodium chloride - NaCl Iron(II) sulfide - FeS

  20. Classification of Matter (Mixtures) Mixtures: • Homogeneous:A mixture having only one phase;it is uniform (the same) throughout and has the same properties throughout. These are called„Solutions”. • Heterogeneous:A mixture with more than one phase. It is non-uniform and does NOThave the same properties throughout.

  21. Matter and Change • Phase - A sample of matter that is uniform in composition and physical state and is separated from other phases by a definite boundary.

  22. Physical Change: A change in which each substance involved in the change retains its original identity and no new elementsor compounds are formed. melting H2O (s) H2O (l)

  23. Matter and Change • Chemical Change: A change in which one or more elements or compounds (substances) are formed. “Reacting” 2 H2 (g) + O2 (g) 2 H2O (l) AgNO3(aq) + HCl(aq) AgCl(s) + HNO3(aq)

  24. Chemical and physical change

  25. جداسازی(Separation)

  26. مخلوط اجزائ مخلوط حلال A B C کروماتوگرافی(Chromatography) 1_17

  27. Paper Chromatography

  28. Measurement • Chemistry is an Observational science. • Chemistry is a Quantitativescience. • Measurement - A quantitative observation.

  29. Measurement All measurements have three parts: 1.A value 26.9762g 2. Units 3.An Uncertainty Examples:33.2 mL 72.36 mm 426 kg 31 people

  30. Measurement Conversion Factors:A fraction whose numerator and denominator contain the same quantity expressed in different units. 1 mile 5280 ft 5280 ft 1 mile 1 mile = 5280 ft = 1 = 1 cm 0.01 m 0.01 m 1 cm = 1 1 cm = 0.01 m = 2.54 cm 1 in 1 in 2.54 cm = 1 1 in = 2.54 cm =

  31. Measurement Uncertainty in Measurements: Exact Measurements: Measured values determined by counting or when a value is defined. Examples: 31 people, 27 rocks, 2.54 cm = 1 in The uncertainty in these measurements = 0 Non-exact Measurements: All other measurements. The last digit recorded isuncertain; it is estimated!! Examples: 27.5 g, 32.7 mm 12 467 km

  32. Measurement Significant Figures: ارقام معنی‌دار Each digit obtained as a result of a measurement includes all of the certaindigits and the first uncertain digit. The number of significant figures in a measurement is an indicator of the sensitivityof the measurement.

  33. Measurement • Rules for Significant Figures: • All non-zero digits are significant. 25.79 km 27 mL • A zero between other significant figures is significant. 207.9 nm 100.7 mL

  34. Measurement • Initial zeros areNOTsignificant: 0.001 23 cm3 • Final zeros after the decimal pointAREsignificant: 23.100ps • Final zeros in a measurement with no decimal point may or may not be significant. 3200 cm (might have 2, 3, or 4 significant figures!!) • Exactmeasurements have an infinite number of significant figures.(They are CERTAIN!!)

  35. Measurement Count from left from first non-zero digit. Significant Figures 3 Number 6.29 g 0.00348 g 9.0 1.0  10-8 100 eggs 100 g 3 2 2 infinite bad notation

  36. (Rounding Off) :گرد کردن Report to 3 significant figures: 10.235  12.4790  19.75  15.639  7.025  10.2 12.5 19.8 15.6 7.02 Note: 3rd digit is increased by one if 4th digit >5 and decreased to zero if 4th digit <5. If 4th digit is =5, 3rd digit is increased only if it is an odd number!

  37. ارقام معنی‌دار: محاسبات ریاضی Adding and subtracting: Use the number of decimal places in the number with the fewestdecimal places. 11.676 + 1.14 + 0.6 13.416  13.4 35.2 mL + 0.34 mL = 35.54 mL = 35.5 mL 1.00794 u + 1.490 u + 15.9994 u = 18.49734 u = 18.497 u

  38. ارقام معنی‌دار: محاسبات ریاضی Multiplying and dividing: Use the fewest significant figures. 4 3 0.01208  0.236 = 0.51186 = 5.12  10-3 (9.5760 g)/(12.2 mL) = 0.785 g/mL 5 3

  39. واحدهای اندازه گیریSI

  40. واحدهای اندازه گیری فرعی Derived Quantities Force Newton N = kg m s-2 Pressure Pascal Pa = kg m-1 s-2 Eenergy Joule J = kg m2 s-2 Other Common Units Length Angstrom Å = 10-8 cm Volume Litre L = 10-3 m3 Energy Calorie cal = 4.184 J Pressure Atmosphere 1 atm = 1.064 x 102 kPa = 760 mm Hg

  41. برگزیده پیشوندهای مورد استفاده درSI

  42. Properties of Matter • Extensive Properties(خاصيت مقدارى): Properties that depend on the amount of matter present in a sample. Mass Volume Heat Capacity • Intensive Properties (خاصيت شدتى): Properties that do NOT depend on the amount of matter present in a sample. Color Temperature Density Melting Point Specific Heat Boiling Point

  43. Temperature and Thermal Energy Temperature: A measure of the “hotness”and “coldness” of an object; a measure of the average kinetic energy of the atoms and molecules of the object. The higher the temperature, the more kinetic energy the atoms and/or molecules have. Thermal Energy: Often called “heat”, it is the form of energy toward which all other forms tend to go.

  44. (Temperature)دما

  45. اندازه گیری دما

  46. تبدیل واحدهای دما کلوینبه سانتی گراد: فارنهایت به سانتی گراد: Note: K and not °K

  47. Sample calculations involving temperatures Example: Convert 73.6 oF to Celsius and Kelvin temperatures. oC = (5/9)(oF - 32) K = oC + 273.15 oC = (5/9)(73.6 oF - 32) = (5/9)(41.6) = 23.1 oC K = 23.1 oC + 273.15 = 296.3 K

  48. حجم

  49. ابزارهای اندازه گیری حجم

  50. Dimensional Analysis How many meters are in each of the following? 21 km 1023570 mm 2.1 x 104 m (21 km)(1 x 103 m) = 21 x 103 m = km (1023570 mm)( 1 m ) = (106mm) 1.023570 m

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