Question | Answer |
Chemical Evolution | The proposition that early in earths history simple chemical compounds in the atmosphere and ocean combined to form larger complex substances. |
Element | |
Atomic Number | The number of protons |
Isotopes | Forms of an element with different numbers of neutrons |
Mass Number | The sum of the protons and neutrons in an atom |
Atomic Mass Unit (amu) | Special unit to measure atoms |
Orbitals | The way elections move around |
Electron Shell | orbitals are grouped into levels |
Valence electrons | the electrons found in each valence shell |
Valence | The number of unpaired electrons found in a atom |
Chemical Bond | Strong attraction that bind atoms together |
Covalent Bond | The shared electrons that glue the atoms together |
Molecules | Substances that are held together by a coolant bond |
Nonpolar covalent bond | An equal sharing of electrons |
Electronegativity | when atoms hold electrons in covalent bonds more tightly than others |
Ionic Bond | The electrons in ionic bonds are completely transferred from one atom to another |
Anion | Negatively charged ions |
Chemical reaction | when one substance is combined with others or broken down into another substance |
Mole | |
Ion | an atom or molecule that carries a charge |
Cation | positively charged ions |
Molecular Formula | Indicates the numbers and types of atoms in a molecule |
Structural Formulas | Indicates which atoms are bonded together |
Mole | Refers to the number 6.022x10^23 |
Molecular Weight | The sum of the mass numbers of all atoms in a molecule |
Solution | A mixture of one or more substances dissolved in a liquid |
Molarity | The number of moles of the substance per liter of the solution |
Solvent | an agent for getting substances into a solution |
Polar | the overall distribution of charge is asymmetrical |
Hydrophillic | Substances that interact with water |
Hydrophobic | substances that do not interact with water |
Cohesion | Binding between like molecules |
Adhesion | Binnding between unlke molecules |
Meniscus | the concave surface that forms in a glass of water . because they experience a downward pull |
Surface tension | the resistance that makes water surface act as if it had an elastic membrane |
specific heat | the amount of energy required to raise the temperature of 1gram of substance by 1 degrease C |
Heat of vaporization | the energy required to change 1gram of a substance from liquid to gas |
Hydrogen ion | H+ |
hydroxide ion | OH- |
Acids | substances that gives up protons during chemical reactions and raise the hydrogen ion concentration of water |
Bases | molecules that acquire protons during chemical reactions and that lower the hydrogen ion concentration of water |
PH | to express the concentration of protons in a solution with a logarithmic form |
Reactant | atoms shown on the left of a chemical equation |
Product | atoms shown on the right of a chemical equation |
Chemical equalilibrium | A dynamic but stable state |
System | A set of interacting elements |
Endothermic | transforming a liquid water molecule to a gaseous state |
Exothermic | the transformation of water vapor to a liquid water and releases heat |
Energy | the capacity to do work or to supply heat |
Potential Energy | Stored energy |
Kinetic Energy | Energy of motion |
Thermal Energy | Kinetic energy of molecular motion |
Temperature | How much thermal energy its molecules possess |
Heat | the transferd energy between two objects with different temperatures when they come in contact |
first law of thermodynamics | states that energy is conserved. cannot be created or destroyed but only transferred and transformed |
Entropy | the amount of disorder in a group of molecules |
Second law of thermodynamics | that entropy always increases in an isolated system |
Exergonic | when chemical reactions are spontaneous because ^G is less than zero |
Endergonic | when chemical reactions are nonspontaneous because ^G is greater than zero |
Free Radicals | the atoms from the result of energy from photons that break molecules apart by knocking electrons away from outer shells of atoms |
Chemical energy | The potential energy stored in chemical bonds |
Organic | Molecules that contain carbon |
Functional groups | H-, N-, and O- containing groups found in organic compounds |