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Introduction: Measurement, Mathematical Operations; Introduction to Chemistry

Topic 1. Introduction: Measurement, Mathematical Operations; Introduction to Chemistry. Measurement.

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Introduction: Measurement, Mathematical Operations; Introduction to Chemistry

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  1. Topic 1 Introduction: Measurement, Mathematical Operations; Introduction to Chemistry

  2. Measurement Measurement,from the Greek word "metron", meaning limited proportion is the estimation of the magnitude of some attribute of an object, such as its length or weight, relative to a unit of measurement It involves using a measuring instrument, such as a ruler or scale, which is calibrated to compare the object to some standard, such as a meter or a kilogram Metrology is the scientific study of measurement

  3. Units of Measurements Imperial system early used as English units then Imperial units came to known as US Customary Units have at times been called foot-pound-second systems Metric System a decimalised system of measurement based on the metre and the gram it has a single base unit for each physical quantity all other units are powers of ten or multiples of ten of this base unit SI Units Système International d'Unités modern, revised form of the metric system two types of SI units, Base and Derived Units

  4. SI Base Units

  5. SI Prefixes

  6. Instruments used for measuring

  7. Example Convert the following measurements: 1. 34 L = _____ cc 2. 25°F = _____ °K 3. 2.0 mg = _____ kg 4. 3.5 hrs = ______ s 5. 1 x 10-5 mol = ______ mol

  8. Example Convert the following measurements: (Answer) 1. 34 L = 34, 000cc 2. 25°F = 244.48 °K 3. 2.0 mg = 0.0000020 kg 4. 3.5 hrs = 12600 s 5. 1 x 10-5 mol = 0.01 mmol

  9. Basic Mathematical Operations MDAS rule Perform multiplication/division first before addition and subtraction e.g. Solve the following: • 32(6+5) – 4/2 + (35+8) • {3[4+8]/6} – (2+5(6)-12)

  10. Basic Mathematical Operations MDAS rule Perform multiplication/division first before addition and subtraction e.g. Solve the following: • 32(6+5) – 4/2 + (35+8) = 393 • {3[4+8]/6} – (2+5(6)-12) = -14

  11. Rounding-off Figures Rule 1: If the digit after that being retained is LESS than 5, the retained digit is unchanged. Rule 2: If the digit after that being retained is GREATER than 5, the retained digit is increased by one. Rule 3: f the digit after that being retained is EQUAL to 5, what follows determines how to round the number. If even number, retained If odd number, increase by 1

  12. Example Round to the nearest hundredths: 1. 2.3560 = _____ 2. 2.3460 = _____ 3. 2.3452 = _____ 4. 2.3453 = _____ 5. 2.3423 = _____

  13. Example Round to the nearest hundredths: (Answer) 1. 2.3560 = 2.36 2. 2.3460 = 2.35 3. 2.3452 = 2.34 4. 2.3453 = 2.35 5. 2.3423 = 2.34

  14. Significant Figures Guidelines for Using Significant Figures • Any digit that is not zero is significant. • Zeros between nonzero digits are significant. • Zeros to the left of nonzero digit are not significant. • If a number is greater than 1, all zeros written after the decimal point is significant. • If a number is less than 1, zeros before the nonzero digit is not significant. • For numbers that do not contain decimal point, the trailing zeros (zero after the nonzero digit) may or may not be significant. • In addition and subtraction, the number of significant figures in the answer is determined by the digit that has the least number of decimal places. • In multiplication and division, the number of significant figures in the product or quotient is determined by the original number that has the least number of significant figures.

  15. Significant Figures Example: • 5.01 • 0.02120 • 7,100 • 7.10 x 103 • 2.456

  16. Significant Figures Example: • 5.01 = 3 • 0.02120 = 4 • 7,100 = 2 • 7.10 x 103 = 3 • 2.456 = 4

  17. Significant Figures Example: • 12,524.1 + 0.1193 • 8.60 x 2.1335 • 0.0154 / 1.3

  18. Significant Figures Example: • 12,524.1 + 0.1193 = 12524.2 • 8.60 x 2.1335 = 18.3 • 0.0154 / 1.3 = 1.2 x 10-2

  19. Scientific Notation In observance of significant figures, scientist used scientific notation to express extremely large or small numerical values. All can be expressed in the form: N x 10n

  20. Scientific Notation Step 1: Find n Step2: Count the number of places that the decimal point must be moved to give the number N. Step 3: If the decimal point has to be moved to the left, n is a positive integer or to the right, n is a negative integer

  21. Scientific Notation Example: • 568213.5 • 18162.07 • 0.000092

  22. Scientific Notation Example: • 568213.5 = 5.682135 x 105 • 18162.07 = 1.816207 x 104 • 0.000092 = 9.2 x 10-5

  23. Accuracy and Precision Accuracy determines how close a measurement is to the true value of the quantity that is being measured. Precision refers to the closeness of two or more measurements of the same quantity with one another.

  24. Error Errorrefers to a difference between actual behavior or measurement and the norms or expectations for the behavior or measurement Two types: 1. Systematic Error (determinate) 2. Random Error (indeterminate)

  25. Error

  26. Chemistry History began with the discovery of fire leads to the purification of metals (metallurgy) alchemy

  27. Alchemy Mission: protoscience to discover the elixir of life (fountain of youth) to create gold through transformation

  28. Alchemy Failure: no scientific method unable to established nomenclature unable to reproduce experiments

  29. Timeline First chemists – the Moslems Geber – the father of chemistry Robert Boyle – alchemist turned chemist differentiate alchemy and chemistry Antoine Lavoisier

  30. Timeline Aristotle “atomos” John Dalton J. J. Thomson Ernest Rutherford

  31. Timeline Chadwick Niels Bohr E. Schrodinger Dmitriv Mendeleyeev

  32. Divisions of Chemistry • Inorganic chemistry is the study of the properties and reactions of inorganic compounds. • Organic chemistry is the study of the structure, properties, composition, mechanisms, and reactions of organic compounds. In other words, it is the study of those substances that contain carbon.

  33. Divisions of Chemistry • Analytical chemistry is the analysis of material samples to gain an understanding of their chemical composition and structure. Analytical chemistry incorporates standardized experimental methods in chemistry. • Biochemistry is the study of the chemicals, chemical reactions and chemical interactions that take place in living organisms. • Physical chemistry is the study of the physical basis of chemical systems and processes. In particular, the energetics and dynamics of such systems and processes are of interest to physical chemists.

  34. Divisions of Chemistry Other subdivisions: Astrochemistry Atmospheric chemistry Chemical Engineering Chemo-informatics Electrochemistry Environmental chemistry Geochemistry Green chemistry History of chemistry Materials science Medicinal chemistry Molecular Biology Molecular genetics Nanotechnology Organometallic chemistry Petrochemistry Pharmacology Photochemistry Phytochemistry Polymer chemistry Supramolecular chemistry Surface chemistry Thermochemistry Theoretical Chemistry Nuclear Chemistry

  35. Thank You!

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