Chem chapter 1

Introduction to Chemistry

• General Organic & Biochemistry

  • Authors: Spencer L. Seager, Michael R. Slabaugh

  • Covers topics related to chemistry and its relevance to health, nutrition, and everyday life.

Matter and Mass

• Matter

  • Defined as anything that has mass and occupies space.

  • Mass

    • Measurement of the amount of matter in an object.

    • It is constant regardless of location (e.g., same mass on Earth and the Moon).

Weight

• Weight

  • Measurement of the gravitational force acting on an object.

  • It varies by location (e.g., 1.0 lb on Earth is approximately 0.17 lb on the Moon).

Physical and Chemical Properties

• Physical Properties

  • Can be observed or measured without changing the matter's composition.

  • Examples include color, shape, mass.

• Chemical Properties

  • Observed by changing the matter into new substances.

  • Examples include flammability and reactivity (e.g., mixing vinegar and baking soda).

Physical and Chemical Changes

• Physical Changes

  • Occur without a change in substance composition.

  • Examples: freezing, melting, evaporation of water.

• Chemical Changes

  • Accompanied by a change in composition.

  • Examples: burning paper, fizzing reaction of vinegar and baking soda.

Particulate Model of Matter

• All matter is made up of tiny particles:

  • Molecules

    • Smallest unit of a pure substance capable of independent existence.

  • Atoms

    • Basic units that make up molecules.

Molecule Classification

• Types of Molecules

  • Diatomic: Contains two atoms.

  • Trioatomic: Contains three atoms.

  • Polyatomic: Contains more than three atoms.

Further Molecule Classification

• Homoatomic Molecules

  • Composed of the same kind of atoms.

• Heteroatomic Molecules

  • Composed of two or more different kinds of atoms.

Molecule Classification Example

• Examples:

  • H2O2: Polyatomic & Heteroatomic

  • H2O: Triatomic & Heteroatomic

  • O2: Diatomic & Homoatomic

Classification of Matter

• Pure Substances

  • Constant composition and fixed properties.

  • Example: Pure water.

• Mixtures

  • Vary in composition and properties.

  • Example: Mixture of sugar and water.

Heterogeneous vs. Homogeneous Mixtures

• Heterogeneous Mixtures

  • Properties depend on location (e.g., pizza pie).

• Homogeneous Mixtures (Solutions)

  • Consistent properties throughout the mixture (e.g., sugar in water).

Elements

• Elements

  • Pure substances made of homoatomic molecules or individual atoms.

  • Example: Oxygen gas (O2) and copper metal (Cu).

Compounds

• Compounds

  • Pure substances made of heteroatomic molecules or ions of different kinds.

  • Example: Water (H2O) and table salt (NaCl).

Matter Classification Summary

• Categories:

  • Matter:

    • Pure Substance

      • Element

      • Compound

    • Mixture

      • Heterogeneous

      • Homogeneous (Solution)

Matter Classification Example

• Classification: H2, F2, HF

  • H2, F2: Elements (homoatomic molecules)

  • HF: Compound (heteroatomic molecules)

Measurements and Units

• Measurements entail a number and a unit (e.g., feet, pounds).

• Units ensure consistency and accuracy in scientific measurements.

Metric System

• Decimal system based on factors of 10.

• Basic Units:

  • e.g., 1 meter (1 m).

• Derived Units:

  • e.g., 1 square meter (1 m²).

Use of Prefixes

• Prefixes relate basic and derived units for easier comprehension.

Temperature Scales

• Common scales: Fahrenheit, Celsius, Kelvin.

• Celsius and Kelvin preferred in scientific work.

Temperature Conversions

• Mathematical equations allow conversion between scales.

Percentage

• Defined as per one hundred.

• Calculating Percentages:

  • Use formula involving total and specific parts.

Density

• Defined as the mass of a sample divided by its volume.

• Density Calculation:

  • Example of calculating density from mass and volume measurements.