Ch. 3 Flashcards
Polar molecule
A molecule containing polar bonds where the sum of all bond’s dipole moments is not 0. The overall charge is unevenly distributed.
Cohesion
The linking together of like molecule, often by hydrogen bonds. The force that holds substances together.
Adhesion
The Clinton of one substance together, such as water to plant cell walls by means of hydrogen bonds. An attraction between different substances.
Surface tension
A measure of how difficult it is to stretch or break the surface of a liquid.
Kinetic energy
The energy of motion.
Thermal energy
Kinetic energy due to the random motion of atoms and molecules, energy in its most random form. Related to temperature, but not the same thing.
Temperature
A measure of energy that represents the average kinetic energy of the molecules in a body of matter, regardless of volume. Whereas, the total thermal energy depends in part on the matters volume.
Objects and temperature
Whenever 2 objects of different temperature are brought together, thermal energy passes from the warmer to the cooler object, until the 2 are the same temperature. Molecules in the cooler object speed up at the expense of the warmer object.
Heat
Thermal energy in transfer from one body of matter to another.
Calorie(cal)
The amount of heat energy required to raise the temperature of 1g of water by 1C, also the amount of heat energy that 1g of water releases when it cools by 1C. The calorie(w/capital C) is usually used to indicate the energy content of food, is really a kilocalorie(kcal).
Joule(J)
A unit of energy: 1J = 0.239 cal; 1 cal = 4.184 J.
Specific heat
The amount of heat that must be absorbed or lost for 1g of a substance to change its temperature by 1C. It can he thought as a measure of how well a substance resists changing its temperature. When it absorbs or releases heat.
Hydrogen bonds & heat
Heat must be absorbed to break hydrogen bonds. Heat is released when hydrogen bonds form.
Heat of vaporization
The quantity of heat a liquid must absorb for 1g of it to be converted from the liquid to the gaseous state. The heat a liquid must absorb for 1g to be converted to gas.
Solution
A liquid that is a homogenous mixture of 2 or more substances.
Solvent
The dissolving agent of a solution.
Solute
The substance that is dissolved.
Acqueous solution
A solution where the solute is dissolved in water. Any solution where the solvent is water. A compound does not meet to be ionic to dissolve in water. Water is the solvent of life.
Hydrophilic
Any substance that has an affinity for water. Substance can be hydrophilic without dissolving.
Colloid
A stable suspension of fine particles in a liquid.
Hydrophobic
Having no affinity for water; tending to coalesce and form droplet in water. Ex. Oil.
Molecular mass
The sum of the masses of all the atoms in a molecule.
Mole(mol)
The number of grams of a substance that equals its molecular or atomic mass in daltons. A mole contains Avogadro’s number of the molecules or atoms in a question.
Avogadro’s number
6.02 x 10^23.
1 mol = 6.02 x 10^23 atoms
au = atomic unit
6.02 x 10^23 daltons = 1g
