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.