Weekly Assessment: Water Molecule & Bonds

Study Notes

Weekly Assessment Topics

Water Molecule Structure: Different diagrams represent the structure and angle of covalent bonds in a water molecule. Specific diagrams are needed to identify the correct structure.
Types of Bonds: Water molecules are primarily held together by covalent bonds. Hydrogen bonds may also form between water molecules.
Plant Water Loss: Plants lose water through stomata in a process called transpiration.
Photosynthesis & Respiration in Hydrologic Cycle: Production and respiration are essential processes in the hydrological cycle. These processes occur in plants and animals.
Water Polarity: Water's polarity results from oxygen having a partial negative charge and hydrogen having a partial positive charge. This is due to differences in electronegativity.
Water Polarity & Properties: Water is a polar molecule; it dissolves many minerals and has a high boiling point due to the presence of hydrogen bonds.
Salt Dissolving in Water: When table salt dissolves in water, sodium and chloride ions are surrounded by water molecules. The attraction is directed by the oxygen side of the water.
Water's Boiling Point: Water has a high boiling point due to hydrogen bonds between its molecules, which require more energy to break.
Water's Properties: Water's polarity allows it to dissolve many substances and creates hydrogen bonds, resulting in its high boiling point and ability to dissolve salts.
pH Measurement: Students measured pH values of different water samples (sea water, fresh water, distilled water, clouds).
pH Values & Water Types Different water types (sea water, fresh water, etc) have different pH values.
Water as a Solvent (Specific example): dissolving table salt, sodium bicarbonate, ammonium chloride. The resulting solutions may have different pH values (neutral, basic, or acidic). This is due to the concentration of hydronium(H+) and hydroxide(OH-).
Solution types (Acidic, Basic, Neutral): Various solutions(water samples) were categorized as either acidic, basic, or neutral based on their pH values.
Hydrolysis: Hydrolysis in water changes the hydrogen ion (H+) and an hydroxide ion (OH-) concentrations.
Water Cycle: Evaporation and precipitation (important processes in the water cycle). Acid rain is formed by atmospheric reactions of water with carbon and sulfur oxides dissolved in the atmosphere. Acid rain chemically dissolves rocks.
pH Values of Various Water Bodies: Sea water, fresh water, clouds, and distilled water have specific pH ranges. Salts and their dissolution in water affect its pH.

General Concepts

Types of Water (Locations): Seawater, fresh water, groundwater, distilled water, and clouds.
pH Values: The measurement of acidity or alkalinity in solutions; a numerical scale ranging from 0 to 14 that indicates the concentration of hydrogen ions or hydronium(H+) or hydroxide (OH-).
General water Properties: Water is a polar molecule, and can dissolve certain substances when it comes into contact with them.