Unit 1: Chemistry of Life Flashcards
What is the difference between intramolecular and intermolecular forces?
Intramolecular forces occur between the atoms of a molecule while intermolecular forces occur between other molecules.
What is electronegativity?
The strength of an atom’s pull on electrons.
What is the difference between hydrophobic and hydrophilic substances?
Hydrophobic substances do not bond to water, and hydrophilic substances do.
What is cohesion?
The bonding between multiple water molecules (hydrogen bonding).
What is surface tension?
The difficulty of breaking or stretching the surface of a liquid.
What is adhesion?
The bonding between unlike molecules (i.e. water to the stem of a plant).
What is transpiration?
The movement of water up plants and out of the stomata (in leaves).
What is thermal energy?
The total amount of kinetic energy in a system.
What is temperature?
A measure of the intensity of heat due to the average kinetic energy of molecules.
Is the specific heat of water high or low? What does this property allow it to do?
The specific heat of water is high. This allows it to act as a “heat bank;” It can absorb and release high amounts of heat without changing significantly in temperature.
What is evaporative cooling?
Molecules with the greatest kinetic energy are vaporized. (Note: Water has a high heat of vaporization.)
Does water expand or contract when freezing? How does this support life on Earth?
Water is one of the only substances to expand when freezing. Ice provides insulation, which can regulate temperature when floating on bodies of water, keeping aquatic organisms alive during colder periods.
What are the solubility properties of water?
Water is known as the “solvent of life.” Hydrophilic molecules, such as cellulose and salts, are ionic and polar. Hydrophobic molecules, such as oils and lipids, are covalent and non-polar.
What is the pH scale?
0-6 = Acidic; More hydronium (H+) ions.
7 = Neutral; Balanced ions.
8-14 = Basic; More hydroxide (OH-) ions.
What are buffers?
Substances that minimize changes in the concentrations of H+ and OH- in a solution (weak acids and bases).
What is dehydration synthesis?
The removal of water to bond molecules.