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OSX_Chemistry2e_Ch01_PPT

Chapter Overview

  • Title: Chemistry in Context

  • Source: OpenStax Chemistry

Chapter Outline

  • 1.1 Chemistry in Context

  • 1.2 Phases and Classification of Matter

  • 1.3 Physical and Chemical Properties

  • 1.4 Measurements

  • 1.5 Measurement Uncertainty, Accuracy, and Precision

  • 1.6 Mathematical Treatment of Measurement Results

Learning Objectives

1.1 Chemistry in Context

  • Outline the historical development of chemistry

  • Exemplify the importance of chemistry in everyday life

  • Describe the scientific method

  • Differentiate among hypotheses, theories, and laws

  • Illustrate macroscopic, microscopic, and symbolic domains

Chemistry in Context

  • Chemistry studies the composition, properties, and interactions of matter.

  • Historical perspectives:

    • Greeks: Four elements (earth, air, fire, water).

    • Alchemists: Transformed base metals into noble metals.

Chemistry as the Central Science

  • Chemistry’s interconnection with STEM disciplines.

  • Alchemy's contributions to manipulating matter were not scientific by modern standards.

Chemistry and Everyday Life

  • Examples of chemistry impacts:

    • Digestion, polymer synthesis for clothing, crude oil refinement.

  • Study of changes in composition, structure, and energy associated with matter.

The Scientific Method

  • Based on observation and experimentation.

  • Hypothesis: Tentative explanation of observations.

  • Theory: Comprehensive explanation subject to testing.

  • Law: Summarizes experimental observations.

Domains of Chemistry

  • Macroscopic Domain: Everyday, visible matter.

  • Microscopic Domain: Imaginative aspects, observable through microscopes.

  • Symbolic Domain: Language for representing components (e.g. chemical symbols).

Phases and Classification of Matter

Basic States of Matter

  • Solid: Fixed shape and volume.

  • Liquid: Flows, takes container shape.

  • Gas: Fills shape and volume of container.

  • Definition: Matter occupies space and has mass.

Plasma: A Fourth State of Matter

  • Plasma: Gaseous state with electrically charged particles.

  • Found in stars, lightning, and in man-made devices like TV screens.

Mass vs. Weight

  • Mass: Amount of matter.

  • Weight: Force of gravity on an object.

  • Mass remains constant regardless of location; weight varies with gravity.

Law of Conservation of Matter

  • Total matter remains constant during conversions; true for chemical and physical changes.

Pure Substances and Mixtures

Types of Pure Substances

  • Elements: Cannot be broken down (e.g. Au, O).

  • Compounds: Composed of different elements chemically bonded (e.g. H2O).

Examples of Changes in Matter

  • Mixtures consist of multiple substances and can be separated physically.

Types of Mixtures

  • Homogeneous: Uniform composition (solutions).

  • Heterogeneous: Varies in composition; visually distinguishable.

Atoms and Molecules

  • Atom: Smallest unit of an element.

  • Molecule: Two or more atoms bonded together.

Physical and Chemical Properties

  • Physical Properties: Characteristics not involving chemical change (density, color).

  • Chemical Properties: Characteristics indicating a substance's ability to undergo chemical changes (flammability, toxicity).

Extensive vs. Intensive Properties

  • Extensive: Depends on amount (mass, volume).

  • Intensive: Independent of amount (density, temperature).

Measurements in Chemistry

  • Provide information that underpins theories and laws. Three kinds:

    • Size/magnitude (number), standard (unit), uncertainty.

SI Units and Measurement Properties

Base Units in SI

  • Length: meter (m)

  • Mass: kilogram (kg)

  • Time: second (s)

  • Temperature: kelvin (K)

Measurement Uncertainty, Accuracy, and Precision

  • Counting measurements are exact; others have varying uncertainty.

  • Use significant figures to convey uncertainty.

Dimensional Analysis for Unit Conversions

  • Convert using equivalent quantities; systematic approach.

Summary of Temperature Conversions

  • Fahrenheit and Celsius Equivalence: 0°C = 32°F, 100°C = 212°F

  • Kelvin Scale: Absolute temperature, where 0 K is the theoretical lowest temperature.

Multiple Choice Questions

  • Definition: A form of assessment where respondents choose the correct answer from a list of options.

  • Structure: Typically consists of a stem (the question) and several answer choices, including one correct answer and several distractors.

  • Advantages:

    • Easy to score and analyze.

    • Can assess a wide range of content and cognitive skills.

    • Reduces guesswork compared to true/false questions.

  • Challenges:

    • May encourage guessing if not enough context is provided.

    • Can be limited in assessing deep understanding of complex concepts.

  • Best Practices:

    • Keep questions clear and concise.

    • Use plausible distractors to challenge the test-taker’s knowledge.

    • Randomize answer choices to minimize order bias.

    • Avoid using negative wording in questions.