Chapter 1 Study_of_Change and Properties of Matter.ppt
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A study about Chemistry. The contents are scientific method, law and theory, definition of chemistry, mixture and types of it, compound, classifications of matter, states of matter, changes and properties, scientific notation and significant figures
Chapter 1 Study_of_Change and Properties of Matter.ppt
- 1. Chemistry: The Study of Change Chapter 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 2. Chemistry: A Science for the 21st Century • Health and Medicine • Sanitation systems • Surgery with anesthesia • Vaccines and antibiotics •Energy and the Environment • Fossil fuels • Solar energy • Nuclear energy 1.1
- 3. Chemistry: A Science for the 21st Century • Materials and Technology • Polymers, ceramics, liquid crystals • Room-temperature superconductors? • Molecular computing? • Food and Agriculture • Genetically modified crops • “Natural” pesticides • Specialized fertilizers 1.1
- 4. 1.2 The Study of Chemistry Macroscopic Microscopic
- 5. The scientific method is a systematic approach to research 1.3 A hypothesis is a tentative explanation for a set of observations tested modified
- 6. A theory is a unifying principle that explains a body of facts and/or those laws that are based on them. 1.3 A law is a concise statement of a relationship between phenomena that is always the same under the same conditions. Atomic Theory Force = mass x acceleration
- 7. 1. Matter is anything that occupies space and has mass. 2. A substance is a form of matter that has a definite composition and distinct properties. Chemistry is the study of matter and the changes it undergoes. 1.4 Sugar Water Gold
- 8. A mixture is a combination of two or more substances in which the substances retain their distinct identities. 1. Homogenous mixture (solution) – The composition of the mixture is the same throughout (at the atomic/molecular level). 2. Heterogeneous mixture – The composition is not uniform throughout. Are these homogeneous? soft drink, milk, solder, salt water Are these heterogeneous? cement, iron filings in sand 1.4
- 9. Physical means can be used to separate a mixture into its pure components. magnet 1.4 distillation
- 10. An element is a substance that cannot be separated into simpler substances by chemical means. • 114 elements have been identified • 82 elements occur naturally on Earth gold, aluminum, lead, oxygen, carbon • 32 elements have been created by scientists technetium, americium, seaborgium 1.4
- 12. A compound is a substance composed of atoms of two or more elements chemically united in fixed proportions. Compounds can only be separated into their pure components (elements) by chemical means. 1.4 Water (H2O) Glucose (C6H12O6) Ammonia (NH3)
- 14. The Three States of Matter 1.5 solid liquid gas
- 15. States of Matter
- 16. Water Properties
- 17. A physical change does not alter the composition or identity of a substance. A chemical change alters the composition or identity of the substance(s) involved. ice melting sugar dissolving in water 1.6 hydrogen burns in air to form water Physical or Chemical?
- 18. Formation of Sodium Chloride
- 19. An extensive property of a material depends upon how much matter is is being considered. An intensive property of a material does not depend upon how much matter is is being considered. • mass • length • volume • density • temperature • color Extensive and Intensive Properties 1.6
- 20. Matter - anything that occupies space and has mass. mass – measure of the quantity of matter SI unit of mass is the kilogram (kg) 1 kg = 1000 g = 1 x 103 g weight – force that gravity exerts on an object weight = c x mass on earth, c = 1.0 on moon, c ~ 0.1 1.7 A 1 kg bar will weigh 1 kg on earth 0.1 kg on moon
- 21. 1.7 International System of Units (SI)
- 22. 1.7
- 23. Volume – SI derived unit for volume is cubic meter (m3 ) 1 cm3 = (1 x 10-2 m)3 = 1 x 10-6 m3 1 dm3 = (1 x 10-1 m)3 = 1 x 10-3 m3 1 L = 1000 mL = 1000 cm3 = 1 dm3 1 mL = 1 cm3 1.7
- 24. Density – SI derived unit for density is kg/m3 1 g/cm3 = 1 g/mL = 1000 kg/m3 density = mass volume d = m V 1.7 A piece of platinum metal with a density of 21.5 g/cm3 has a volume of 4.49 cm3 . What is its mass? d = m V m = d x V = 21.5 g/cm3 x 4.49 cm3 = 96.5 g
- 25. K = 0 C + 273.15 0 F = x 0 C + 32 9 5 1.7 273 K = 0 0 C 373 K = 100 0 C 32 0 F = 0 0 C 212 0 F = 100 0 C
- 26. Convert 172.9 0 F to degrees Celsius. 0 F = x 0 C + 32 9 5 0 F – 32 = x 0 C 9 5 x (0 F – 32) = 0 C 9 5 0 C = x (0 F – 32) 9 5 0 C = x (172.9 – 32) = 78.3 9 5 1.7
- 27. 1.8 Scientific Notation The number of atoms in 12 g of carbon-12: 602,200,000,000,000,000,000,000 6.022 x 1023 The mass of a single carbon atom in grams: 0.0000000000000000000000199 1.99 x 10-23 N x 10n N is a number between 1 and 10 n is a positive or negative integer
- 28. Scientific Notation 1.8 568.762 n > 0 568.762 = 5.68762 x 102 move decimal left 0.00000772 n < 0 0.00000772 = 7.72 x 10-6 move decimal right Addition or Subtraction 1. Write each quantity with the same exponent n 2. Combine N1 and N2 3. The exponent, n, remains the same 4.31 x 104 + 3.9 x 103 = 4.31 x 104 + 0.39 x 104 = 4.70 x 104
- 29. Scientific Notation 1.8 Multiplication 1. Multiply N1 and N2 2. Add exponents n1 and n2 (4.0 x 10-5 ) x (7.0 x 103 ) = (4.0 x 7.0) x (10-5+3 ) = 28 x 10-2 = 2.8 x 10-1 Division 1. Divide N1 and N2 2. Subtract exponents n1 and n2 8.5 x 104 ÷ 5.0 x 109 = (8.5 ÷ 5.0) x 104-9 = 1.7 x 10-5
- 30. Significant Figures 1.8 • Any digit that is not zero is significant 1.234 kg 4 significant figures • Zeros between nonzero digits are significant 606 m 3 significant figures • Zeros to the left of the first nonzero digit are not significant 0.08 L 1 significant figure • If a number is greater than 1, then all zeros to the right of the decimal point are significant 2.0 mg 2 significant figures • If a number is less than 1, then only the zeros that are at the end and in the middle of the number are significant 0.00420 g 3 significant figures
- 31. How many significant figures are in each of the following measurements? 24 mL 2 significant figures 3001 g 4 significant figures 0.0320 m3 3 significant figures 6.4 x 104 molecules 2 significant figures 560 kg 2 significant figures 1.8
- 32. Significant Figures 1.8 Addition or Subtraction The answer cannot have more digits to the right of the decimal point than any of the original numbers. 89.332 1.1 + 90.432 round off to 90.4 one significant figure after decimal point 3.70 -2.9133 0.7867 two significant figures after decimal point round off to 0.79
- 33. Significant Figures 1.8 Multiplication or Division The number of significant figures in the result is set by the original number that has the smallest number of significant figures 4.51 x 3.6666 = 16.536366 = 16.5 3 sig figs round to 3 sig figs 6.8 ÷ 112.04 = 0.0606926 2 sig figs round to 2 sig figs = 0.061
- 34. Significant Figures 1.8 Exact Numbers Numbers from definitions or numbers of objects are considered to have an infinite number of significant figures The average of three measured lengths; 6.64, 6.68 and 6.70 = ? 6.64 + 6.68 + 6.70 3 = 6.67333 = 6.67 Because 3 is an exact number = 7
- 35. Accuracy – how close a measurement is to the true value Precision – how close a set of measurements are to each other accurate & precise precise but not accurate not accurate & not precise 1.8
- 36. 1.9 Dimensional Analysis Method of Solving Problems 1. Determine which unit conversion factor(s) are needed 2. Carry units through calculation 3. If all units cancel except for the desired unit(s), then the problem was solved correctly. given quantity x conversion factor = desired quantity given unit x = desired unit desired unit given unit
- 37. 1.9 Dimensional Analysis Method of Solving Problems Conversion Unit 1 L = 1000 mL 1L 1000 mL 1.63 L x = 1630 mL 1L 1000 mL 1.63 L x = 0.001630 L2 mL How many mL are in 1.63 L?
- 38. The speed of sound in air is about 343 m/s. What is this speed in miles per hour? 1 mi = 1609 m 1 min = 60 s 1 hour = 60 min 343 m s x 1 mi 1609 m 60 s 1 min x 60 min 1 hour x = 767 mi hour meters to miles seconds to hours 1.9 conversion units
- 41. Chemistry In Action: In 1940 George Gamow hypothesized that the universe began with a gigantic explosion or big bang. Experimental Support • expanding universe • cosmic background radiation • primordial helium 1.3 Primordial Helium and the Big Bang Theory
- 42. Chemistry In Action On 9/23/99, $125,000,000 Mars Climate Orbiter entered Mar’s atmosphere 100 km (62 miles) lower than planned and was destroyed by heat. 1.7 1 lb = 1 N 1 lb = 4.45 N “This is going to be the cautionary tale that will be embedded into introduction to the metric system in elementary school, high school, and college science courses till the end of time.”