Chemistry Week 1 Key Terms and Concepts (copy)

Key Terms

  • Accuracy: How closely a measurement aligns with a correct value.

  • Atom: Smallest particle of an element that can enter into a chemical combination.

  • Celsius (°C): Unit of temperature; water freezes at 0 °C and boils at 100 °C on this scale.

  • Chemical Change: Change producing a different kind of matter from the original kind.

  • Chemical Property: Behavior related to the change of one kind of matter into another.

  • Chemistry: The study of the composition, properties, and interactions of matter.

  • Compound: Pure substance that can be decomposed into two or more elements.

  • Cubic Centimeter (cm³ or cc): Volume of a cube with an edge length of exactly 1 cm.

  • Cubic Meter (m³): SI unit of volume.

  • Density: Ratio of mass to volume of a substance.

  • Dimensional Analysis (Factor-label method): Mathematical approach for computations, including unit conversions.

  • Element: Substance composed of a single type of atom; cannot be decomposed chemically.

  • Exact Number: Number derived by counting or by definition.

  • Extensive Property: Property depending on the amount of the substance (e.g., mass).

  • Fahrenheit: Unit of temperature; water freezes at 32 °F and boils at 212 °F on this scale.

  • Gas: State where matter has neither definite volume nor shape.

  • Heterogeneous Mixture: Combination of substances with varying composition from point to point.

  • Homogeneous Mixture: (Solution) Combination of substances with uniform composition throughout.

  • Hypothesis: Tentative explanation of observations, guiding further information gathering.

  • Intensive Property: Property of a substance independent of the amount (e.g., density).

  • Kelvin (K): SI unit of temperature; 273.15 K = 0 °C.

  • Kilogram (kg): Standard SI unit of mass; approximately 2.2 pounds.

  • Law: Statement summarizing many observations, predicting aspects of the natural world.

  • Law of Conservation of Matter: Matter may change form, but total amount remains constant.

  • Length: Measure of one dimension of an object.

  • Liquid: State of matter with definite volume but indefinite shape.

  • Liter (L): (Cubic decimeter) Unit of volume; 1 L = 1,000 cm³.

  • Macroscopic Domain: Realm of everyday, visible matter.

  • Mass: Fundamental property indicating the amount of matter.

  • Matter: Anything occupying space and having mass.

  • Meter (m): SI unit of length; 1 m ≈ 1.094 yards.

  • Microscopic Domain: Realm of entities too small to be sensed directly.

  • Milliliter (mL): 1/1,000 of a liter; equal to 1 cm³.

  • Mixture: Matter that can be separated by physical means.

  • Molecule: Bonded collection of two or more atoms of the same or different elements.

  • Physical Change: Change in state or properties without altering chemical composition.

  • Physical Property: Characteristic of matter not associated with changes in composition.

  • Plasma: Gaseous state with a large number of charged atoms/molecules.

  • Precision: How closely measurements match when repeated.

  • Pure Substance: Homogeneous substance with constant composition.

  • Rounding Procedure: Used to reflect uncertainty in calculations.

  • Scientific Method: Path from question and observation to law/hypothesis, verified by experiments.

  • Second (s): SI unit of time.

  • SI Units: Standards fixed by international agreement.

  • Significant Figures: Measured digits including the uncertain last digit.

  • Solid: State of matter with defined shape and constant volume.

  • Symbolic Domain: Language representing components of macroscopic and microscopic domains.

  • Temperature: Intensive property representing hotness or coldness.

  • Theory: Well-substantiated, comprehensive explanation of a nature aspect.

  • Uncertainty: Estimate of measurement difference from the true value.

  • Unit: Standard of comparison for measurements.

  • Unit Conversion Factor: Ratio of equivalent quantities in different units.

  • Volume: Amount of space occupied by an object.

  • Weight: Force gravity exerts on an object.

Key Equations Summary

1.1 Chemistry in Context

  • Chemistry focuses on the composition, structure, and properties of matter and the ways various forms of matter may interconvert.

  • It occupies a central role in science and technology, allowing chemists to perform experiments, pose hypotheses, create laws, and develop theories.

  • Chemists utilize the scientific method to understand natural behaviors, operating in the macroscopic, microscopic, and symbolic domains, and measure, analyze, purify, and synthesize substances essential to life.

1.2 Phases and Classification of Matter

  • Definition of Matter: Anything that occupies space and has mass.

  • Atom: Basic building block; smallest unit of an element that can form combinations.

  • States of Matter:
      - Solid: Fixed shape and volume.
      - Liquid: Variable shape, fixed volume.
      - Gas: Variable shape and volume.
      - Plasma: High temperature gaseous state.

  • Mixtures: Most matter is a mixture of different types of matter that can vary in composition and be separated physically.
      - Heterogeneous Mixtures: Composition varies from point to point.
      - Homogeneous Mixtures: Uniform composition throughout.

  • Pure Substances:
      - Element: Made of one type of atom, cannot be broken down chemically.
      - Compound: Made of two or more types of atoms.

1.3 Physical and Chemical Properties

  • Distinction between physical and chemical properties and changes:
      - Physical Properties: Characteristics like hardness and boiling point; involve no composition change.
      - Chemical Properties: Characteristics like flammability and acidity; involve changes leading to different matter.

  • Properties are categorized:
      - Extensive Properties: Depend on amount present (e.g., mass).
      - Intensive Properties: Independent of amount present (e.g., density).

  • Example of properties:
      - Extensive: Heat.
      - Intensive: Temperature.

1.4 Measurements

  • Measurements are vital for providing quantitative data necessary in chemistry. Each measurement consists of:
      - Amount: The measurement value.
      - Unit for Comparison: Standard for the measurement.