Chemistry of Life Flashcards

Ionic Bonds

• Form between oppositely charged ions (positive and negative)

• An ion is an atom that has gained or lost one or more electrons—and they become a charged particle

Covalent Bonds

Forms when atoms share a pair of electrons

Hydrogen Bonds

Positive charge from hydrogen atom of one water molecule can attract a negative charge from another

Solution

Formed when one substance dissolves in another

Solvent

Dissolves other substances

Solute

Dissolves in a substance

Like dissolves like

• Polar solvents dissolve polar solutes

• Nonpolar solvents dissolve nonpolar solutes

• Polar and nonpolar generally remain seperate (polar forces/bonds require energy to break)

Universal Solvent

Is water, it dissolves everything (highly polar molecules)

Properties of water

• Surface tension

• Cohesion

• Adhesion

• Capillary action

• High specfifc heat

Surface Tension

The elastic sheet-like property of the surface of a liquid caused by intermolecular forces. Produced by cohesion.

Cohesion

Intermolecular attraction between water molecules

Adhesion

The attraction between other molecules (wall) and water molecules

Capillary Action

Movement of liquid through tiny spaces due to adhesion and cohesion working with surface tension often against gravity (tube)

What properties of water are hydrogen bonds responsible for?

• High specific heat

• Cohesion

• Adhesion (produces concave meniscus)

Desalination

Processes that remove excess NaCl and other minerals from water to obtain freshwater suitable for consumption or irrigation. If almost all salt is removed, for human consumption, sometimes produces table salt as a byproduct. Can be done by reverse osmosis, thermal deslination, or electrolysis.

Reverse Osmosis

Uses principles of osmosis to remove salt/impurities, by transferring water through a series of semi-permeable membranes (pretreatment and RO removes contaminants). 2 gallons of sea water=1 gallon of drinking water

Thermal desalination

Uses heat (often from power plants/refineries) to evaporate and condense water to purify it. In advanced desalination plants, water is pretreated to improve efficiency. Heat water and gather the pure water when vapor cools and condensation occurs.

Electrolysis

Utilizes electric potential to move salts through a membrane. Sends an electric charge through the solution to draw metal ions to positive plate and salt to negative plate.

Important compounds in living things

• Water (H2O)

• Carbon Dioxide (CO2)

• Oxygen (breathable) (O2)

• Glucose (C6H12O6)

• All 4 are used in metabolic processes—photosynthesis and cellular respiration

Other important compounds in biology

• Calcium Carbonate (CaCO3)

• Methane (CH4)

• Chitin (C8H13O5N)

• Cellulose (C6H10O5)

• Salt (NaCl)

Important elements in the human body (96%)

• 96% of human body mass:

  • Carbon (C)

  • Hydrogen (H)

  • Oxygen (O)

  • Nitrogen (N)

• CHON

Important elements in the human body (4%)

• Calcium (Ca)

• Iron (Fe)

• Phosphorous (P)

• Potassium (K)

• Sodium (Na)

• Sulfur (S)

• Several other trace elements

• CIPPSS