Unit 1.1 Water Marine Science

First one

Explain the changes of state in water (solid, liquid, gas) in terms of kinetic particle theory.

As energy is added, particles move faster. In solids, particles vibrate in fixed positions. In liquids, they have enough energy to slide past each other. In gases, they move rapidly and independently as attractive forces are broken.

Describe the structure of an atom.

An atom consists of a central nucleus containing protons (positive) and neutrons (neutral), surrounded by electrons (negative) arranged in shells.

Describe the covalent bonding in a water molecule (H2O).

Two hydrogen atoms each share a pair of electrons with one oxygen atom to fill their outer shells.

Describe the ionic bonding in sodium chloride (NaCl).

Sodium loses an electron to become a positive ion (Na+); Chlorine gains that electron to become a negative ion (Cl-). The bond is the electrostatic attraction between these oppositely charged ions.

State the chemical name and formula of three common salts found in sea water.

1. Sodium chloride (NaCl), 2. Magnesium sulfate (MgSO4), 3. Calcium carbonate (CaCO3).

Explain the formation of hydrogen bonds in water.

Water is polar; the oxygen atom is slightly negative (delta-) and the hydrogens are slightly positive (delta+). A hydrogen bond forms from the attraction between the delta+ hydrogen of one molecule and the delta- oxygen of an adjacent molecule.

Explain how hydrogen bonding affects the density of water.

When freezing, hydrogen bonds hold molecules in a rigid, open lattice structure. This pushes molecules further apart, making ice less dense than liquid water so it floats.

Explain how hydrogen bonding affects the specific heat capacity of water.

Water has a high specific heat capacity because significant energy is required to break hydrogen bonds before the molecules can move faster and raise the temperature.

Explain how hydrogen bonding affects the solvent action of water.

The polarity of water molecules allows them to surround and interact with other ionic or polar substances (like salts), pulling them into solution.

Identify whether these are covalent or ionic: O2, NaCl, SO2, CaCO3, CO2, Glucose.

Covalent: O2, SO2, CO2, Glucose. Ionic: NaCl, CaCO3.