AICE Marine Science Chapter 1 Review

Chapter #1 - Water

1.1 Particle Theory and Bonding

  • Kinetic Particle Theory: Matter is composed of particles in constant, random motion. Water exists in three states: solid, liquid, and gas.

  • Processes of Water Change:

    • Freezing - Process A

    • Melting - Process B

    • Condensation - Process C

    • Evaporation - Process D

1.2 Density and Pressure

  • Density: The mass of water per volume. Denser water sinks while less dense water rises.

    • Importance: Ice floats on water due to lower density, providing insulation and habitat.

  • Factors Affecting Density:

    1. Temperature: Density decreases with increasing temperature; warm water floats.

    2. Salinity: Increased salinity raises density; fresh water sits on top of salty water.

    3. Pressure: Increased depth raises pressure, thereby increasing density.

1.1 Particle Theory and Bonding Details

  • Atoms: Basic unit of matter, containing subatomic particles:

    • Protons: + charge

    • Neutrons: Neutral

    • Electrons: - charge, arranged in shells around the nucleus.

      • First shell: Holds up to 2 electrons

      • Second shell: Holds up to 8 electrons

Bonding Properties of Atoms

  • Compounds: Substances formed by a specific ratio of elements bonded together with unique properties (e.g., water).

    • Emergent properties: New characteristics of compounds that don't exist in individual elements.

Types of Bonds Formed by Atoms

Covalent Bonds

  • Formed via sharing of electron pairs; strong and hard to break.

  • Common in non-metals (e.g., H2O, CO2).

    • Water: Each molecule contains two covalent bonds connecting oxygen to hydrogen.

Ionic Bonds

  • Formed by attraction between positively and negatively charged ions that result from electron transfer.

    • Examples: Sodium chloride (NaCl), calcium carbonate (CaCO3).

Hydrogen Bonds

  • Formed between hydrogen and electronegative atoms like oxygen or nitrogen; weaker than covalent bonds.

  • Water's polar nature contributes to its unique properties due to hydrogen bonding:

    • Universal Solvent: Can dissolve many substances due to its polarity.

    • High Specific Heat Capacity: Can absorb significant heat due to many hydrogen bonds, modulating climate.

    • Density Variance with State: Ice has lower density compared to liquid water due to molecular arrangement during freezing.

1.2 Solubility in Water

  • Solution: Mixture of solvent and solute.

    • Solvent: Dissolving substance (e.g., water).

    • Solute: Substance that is dissolved (e.g., salt).

    • Solubility: Extent to which a substance can dissolve in a solvent.

  • Example: Sodium chloride dissolving in water; water molecules surround ions, breaking ionic bonds.

Physical Factors Affecting Solubility

  • Temperature: Higher temperatures increase the rate of dissolution; warmer seawater holds more salt.

  • Salinity: Measured in parts per thousand (ppt).

    • Average salinity: 35 ppt in the open ocean, varies with precipitation and evaporation contributing to salinity changes.

1.2 pH Scale

  • Measures hydrogen ion concentration:

    • Acidic solutions: pH < 7

    • Alkaline solutions: pH > 7

    • Neutral solution: pH = 7

    • Ocean average pH: 8.2.

Gases Solubility in Seawater

  • Concentration equilibrium with atmospheric gases; factors influencing solubility include:

    • Turbulence: Enhances gas dissolution.

    • Water Temperature: Cold water holds more gases than warm.

    • Pressure: Increased depth increases solubility.

    • Salinity: Lower salinity increases gas solubility.

Impact of Solubility on Marine Life

  • Oxygen Minimum Layer (OML): Depths around 100m - 1000m show lowest dissolved oxygen due to lack of light for photosynthesis. Adaptations of organisms in this layer may include specialized gills.

  • Below the OML, oxygen concentrations increase due to low food resources and higher solubility at colder temperatures.

Conclusions

Overall, understanding particle interactions, bonding types, solubility, and their effects on marine environments is key for comprehending ocean chemistry and biology.