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Unit 1 Intro to Chemistry and Measurement

Unit 1 Intro to Chemistry and Measurement. Chemistry I Mr. Patel SWHS. Topic Outline. Learn Major Elements and Symbols Intro to Chemistry (1.1, 1.2) Significant Figures (3.1) Measurement (3.1, 3.2) Factor-Label Method of Conversions (3.3). Intro to Chemistry.

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Unit 1 Intro to Chemistry and Measurement

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  1. Unit 1Intro to Chemistry and Measurement Chemistry I Mr. Patel SWHS

  2. Topic Outline • Learn Major Elements and Symbols • Intro to Chemistry (1.1, 1.2) • Significant Figures (3.1) • Measurement (3.1, 3.2) • Factor-Label Method of Conversions (3.3)

  3. Intro to Chemistry • Matter – anything that has mass and occupies space • Chemistry – study of the composition of matter and the changes it undergoes

  4. Intro to Chemistry • Chemistry affects all aspects of life and other natural events! • Food Digestion • Leaves changing colors • Muscle contraction • Driving cars

  5. Intro to Chemistry • Five different areas or branches of chemistry

  6. Organic Chemistry • Study of all chemicals containing carbon

  7. Inorganic Chemistry • Study of chemicals that do not contain carbon

  8. Biochemistry • Study of processes that occur in living things

  9. Analytical Chemistry • Study that focuses on the composition of matter

  10. Physical Chemistry • Area that deals with the rate, mechanism, and energy transfer of chemistry

  11. Types of Research • Pure Chemistry – increase chemical knowledge • Applied Chemistry – goal oriented

  12. History of Chemistry • Alchemy - change other metals to gold • Lavoisier – Father of Modern Chemistry • Observation to measurement

  13. Scientific Method

  14. Significant Figures • Sometimes we estimate numbers • If we measure between 9.8 and 9.9, we may say it is 9.85. • We know that the 9 and 8 are definite; 5 is estimated. • Discuss accuracy/precision later • Significant Figures – the digits from a measurement that are known precisely plus an estimated digit

  15. Rules for Counting Significant Figures • Every nonzero number is significant (sig.) • 1453 = 4 sig fig • Zeros between nonzero numbers are sig. • 300205 = 6 sig fig • Leftmost zeros in front of nonzeros are NOT sig. (placeholders) • 0.000356 = 3 sig fig • Zeros at end of a number are significant if there is a decimal point • 900.00 = 5 sig fig • Zeros at the end of a number are NOT significant if there is NOT a decimal point • 900 = 1 sig fig • Counting numbers and exact numbers have an infinite number of sig. figures • 23 people = infinite

  16. Significant Figure – My Way • Just think about the Atlantic and Pacific Oceans in relation to the USA • Is the decimal point Absent (Atlantic) or Present (Pacific) • Choose direction: Start at that “ocean” and come toward the USA (number) • Stop at first NONZERO number • Count that number and everything after

  17. Sig Fig Practice • 5005 • 63.207 • 9050 • 3.00 • 0.00509 • 0.00003 • 7000 • 4 sig fig • 5 sig fig • 3 sig fig • 3 sig fig • 3 sig fig • 1 sig fig • 1 sig fig

  18. Calculations with Sig. Fig. • When ROUNDING, choose the number of sig figs needed. Look at the number to the right of last sig fig to determine if you need to round. • Special rules for adding/subtracting and multiplying/dividing

  19. Adding/Subtracting Sig Fig • Answer to addition or subtraction problem should contain the same number of decimal places (not sig fig) as original number with the least decimal places. • Ex: 12.52 + 349.0 + 8.24 • Sum is 369.76 • But 349.0 has only ONE decimal place • ANSWER is 369.8

  20. Sig Fig Add/Subtract Practice • 61.2 + 9.35 + 8.6 • 9.44 – 2.11 • 1.36 + 10.17 • 34.61 – 17.3 • 14.2 + 8.73 + 0.912 • 79.2 • 7.33 • 11.53 • 17.3 • 23.8

  21. Multiply/Divide Sig Fig • Answer to multiplication or division problem should contain the same number of significant figures as original number with the least significant figures. • Ex: 7.55 x 0.34 • Product is 2.567 • But 0.34 has only TWO sig figs • ANSWER is 2.6

  22. Sig Fig Multiply/Divide Practice • 2.10 x 0.70 • 2.4526 / 8.4 • 8.3 x 2.22 • 8432 / 12.5 • 22.4 x 11.3 x 5.2 • 1.5 • 0.29 • 18 • 675 • 1300

  23. Measurement • Measurement – quantity with a number and unit • Accuracy – how close you are to the true value • Precision – how close your measurements are to one another

  24. Scientific Notation • Used for very large or very small numbers • Converts a single number to a product of two numbers • Ex: 8000  8 x 103 • Ex: 0.234  2.34 x 10-1

  25. Scientific Notation Practice • 252 • 125000 • 0.00305 • 0.00000000548 • 2.52 x 102 • 1.25 x 105 • 3.05 x 10-3 • 5.48 x 10-9

  26. International System of Units (SI) • Five SI base units: • meter (length) • kilogram (mass) • Kelvin (temperature) • Second (time) • Mole (amount)

  27. Metric Conversions

  28. Factor-Label Method • Write down starting and ending unit • Write all relevant conversion factors • Cancel units to get to end unit • To cancel a unit, the unit must be on the top and bottom

  29. Conversion Examples

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