Particle Theory
What happens to particle movement when water is heated?
Particles move faster when water is heated.
What type of bond holds hydrogen and oxygen together in a water molecule?
A covalent bond holds hydrogen and oxygen together in a water molecule.
Why is water considered a universal solvent?
Water dissolves many substances because its polarity allows it to surround and separate ions/molecules.
Name one major ion found in seawater.
Major ions include sodium (Na⁺) or chloride (Cl⁻).
What happens to water density as temperature decreases?
Density increases as temperature decreases (until 4°C).
Describe the arrangement of particles in a solid vs. a liquid.
In a solid, particles are tightly packed and vibrate; in a liquid, they are close but can move/flow past each other.
Draw or describe the shape of a water molecule.
Water is bent/V‑shaped, with oxygen at the center and two hydrogens at an angle (~104.5°).
Define cohesion and give one marine example.
Cohesion = water molecules sticking together, example: formation of water droplets.
Why is seawater considered a mixture?
Seawater is a mixture because it contains dissolved salts, gases, and organic materials.
Define pressure in the context of the ocean.
Pressure is the force exerted per unit area by the weight of water above.
Explain why water expands when it freezes.
Water expands when it freezes because hydrogen bonding forces molecules into an open hexagonal structure.
Explain why water is a polar molecule.
Water is polar because oxygen is more electronegative, pulling electrons closer and creating partial charges.
Explain surface tension and how it benefits marine organisms.
Surface tension is caused by hydrogen bonding at the surface, it allows organisms like water striders to rest on water.
Explain how temperature affects gas solubility in seawater.
Gas solubility decreases as temperature increases (warm water holds less oxygen).
Why does pressure increase with depth?
Pressure increases with depth because more water is stacked above, adding weight.
How does kinetic particle theory explain evaporation?
In evaporation, particles with the highest kinetic energy escape the liquid surface into the gas phase.
How do hydrogen bonds form between water molecules?
Hydrogen bonds form when the partially positive hydrogen of one molecule is attracted to the partially negative oxygen of another.
Why does water have a high latent heat of vaporization?
Water has a high latent heat of vaporization because hydrogen bonds require lots of energy to break.
Why does oxygen concentration vary with depth?
Oxygen varies with depth due to photosynthesis at the surface, respiration throughout the water column, and limited mixing at depth.
Explain how salinity affects density.
Higher salinity increases density because dissolved ions add mass.
Compare the energy changes involved in melting vs. boiling.
Melting requires less energy because only some bonds are broken, boiling requires much more energy to fully separate particles into gas.
Explain how water’s molecular structure leads to its high specific heat capacity.
Water’s polarity and hydrogen bonding require large amounts of energy to increase temperature, giving it a high specific heat capacity.
Describe how water’s thermal properties help regulate ocean temperature.
Water absorbs heat slowly and releases it slowly, helping stabilize ocean temperatures and climate.
Describe how salinity affects the solubility of gases and nutrients.
Higher salinity reduces gas solubility; nutrients may become more or less available depending on ionic interactions.
Describe how density differences drive ocean circulation.
Density differences (from temperature and salinity) create convection currents that drive thermohaline circulation.