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Chem 105 Kristen Kull SIMS 115

Chem 105 Kristen Kull SIMS 115. Kristen Kull CHEM105 General  Chemistry I (Kull) Course Information Course Schedule WebCT http:<br>ow.brookscole.comkotz6e. Chapter 1 Matter and Measurement 1.1 Classifying matter. Matter consists of atoms and molecules in motion. STATES OF MATTER.

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Chem 105 Kristen Kull SIMS 115

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  1. Chem 105 Kristen KullSIMS 115 Kristen Kull CHEM105 General  Chemistry I (Kull) Course Information Course Schedule WebCT http:\\now.brookscole.com\kotz6e Chapter 1 Lesson 1

  2. Chapter 1 Matter and Measurement1.1 Classifying matter Matter consists of atoms and molecules in motion Chapter 1 Lesson 1

  3. STATES OF MATTER • SOLIDS — have rigid shape, fixed volume. External shape can reflect the atomic and molecular arrangement. • Reasonably well understood. • LIQUIDS — have no fixed shape and may not fill a container completely. • Not well understood. • GASES— expand to fill their container. • Good theoretical understanding. Chapter 1 Lesson 1

  4. 1.2 Elements and atoms • Periodic table – names, symbols, massesof • CHEMICAL ELEMENTS - • pure substances that cannot be decomposed by ordinary means to other substances. • An atom is the smallest particle of an element that has the chemical properties of the element. • An atom consists of a nucleus (of protonsand neutrons) and electrons in space about the nucleus. Chapter 1 Lesson 1

  5. 1.3 Compounds and Molecules • Compound – two or more different elements • When elements are part of a compound, original properties are replaced by characteristic properties • AMOLECULEis the smallest unit of a compound that retains the chemical characteristics of the compound. Chapter 1 Lesson 1

  6. 1.4 Physical properties • Properties which can be measured without changing the composition of the substance • Chemists are interested in the nature of matter and how this is related to its atoms and molecules. • Graphite: layer structure of carbon atoms reflects physical properties. Chapter 1 Lesson 1

  7. Physical Properties-color-melting and boiling point-odor Physical Changes • boiling of a liquid • melting of a solid • dissolving a solid in a liquid to give a homogeneous mixture — a SOLUTION. Chapter 1 Lesson 1

  8. Intensive property – not dependent on quantity (density) • Extensive property – varies with quantity (mass) Chapter 1 Lesson 1

  9. Platinum Mercury Aluminum DENSITY - an important and useful physical property 13.6 g/cm3 21.5 g/cm3 2.7 g/cm3 Chapter 1 Lesson 1

  10. Problem A piece of copper has a mass of 57.54 g. It is 9.36 cm long, 7.23 cm wide, and 0.95 mm thick. Calculate density (g/cm3). Chapter 1 Lesson 1

  11. Strategy 1. Get dimensions in common units. 2. Calculate volume in cubic centimeters. 3. Calculate the density. Chapter 1 Lesson 1

  12. SOLUTION 1. Get dimensions in common units. 2. Calculate volume in cubic centimeters. 3. Calculate the density. (9.36 cm)(7.23 cm)(0.095 cm) = 6.4 cm3 Note only 2 significant figures in the answer! Chapter 1 Lesson 1

  13. PROBLEM: Mercury (Hg) has a density of 13.6 g/cm3. What is the mass of 95 mL of Hg in grams? In pounds? Solve the problem using DIMENSIONAL ANALYSIS. Chapter 1 Lesson 1

  14. PROBLEM: Mercury (Hg) has a density of 13.6 g/cm3. What is the mass of 95 mL of Hg? Strategy 1. Use density to calc. mass (g) from volume. 2. Convert mass (g) to mass (lb) Need to know conversion factor = 454 g / 1 lb First, note that 1 cm3 = 1 mL Chapter 1 Lesson 1

  15. PROBLEM: Mercury (Hg) has a density of 13.6 g/cm3. What is the mass of 95 mL of Hg? 1. Convert volume to mass ( 95 cm3 )(13.6 g/cm3) = 1.3 x 103 g 2. Convert mass (g) to mass (lb) Chapter 1 Lesson 1

  16. 1.5 Physical and Chemical changes • Physical change: identity is preserved; not always the state (melting point) • Chemical change: new substances are produced Chapter 1 Lesson 1

  17. 1.6 Units of Measurement • Qualitative: no measurements or numbers involved ex. color (observations) • Quantitative: numerical information ex. Time, mass, volume • Metric (SI) base units Table 1.2, page 26 • Selected prefixes used in the metric system, Table 1.3, page 27 Chapter 1 Lesson 1

  18. 212 ˚F 100 ˚C 373 K 100 K 180˚F 100˚C 32 ˚F 0 ˚C 273 K Temperature Scales Fahrenheit Celsius Kelvin Boiling point of water Freezing point of water Notice that 1 kelvin degree = 1 degree Celsius • T (˚C) = 5/9 [T(˚F) – 32] • T (K) = t (˚C) + 273.15 Chapter 1 Lesson 1

  19. Precision: how well several values agree Standard deviation Accuracy: how close to the accepted value Percent error 1.7 Making measurements Chapter 1 Lesson 1

  20. 1.8 Mathematics of Chemistry • Exponential or scientific notation • No more significant than least significant • Dimensional Analysis • Always write your units; one will always cancel out Chapter 1 Lesson 1

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