Chemistry Flashcards

4244849342	Matter	Any substance that has mass and occupies space	0
4244850105	Element	Any substance that cannot be broken down to any other substance by ordinary chemical means	1
4244851665	Atom	The smallest unit of an element that contains all the characteristics of that atom; the building blocks of matter	2
4244855162	Nucleus	The central core in atoms composed of positively charged protons and neutral neutrons	3
4244856290	Proton	Positively charged subatomic particle that makes up the nucleus of an atom	4
4244857691	Neutron	Subatomic particle that has no charge and makes up the nucleus of an atom	5
4244858704	Electron	Negatively charged subatomic particles located in orbitals around the nucleus of an atom	6
4244860543	Atomic Number	The number of protons in an atom which defines the element	7
4244861510	Atomic Mass	The sum of the masses of protons and neutrons of an atom; electrons aren't necessarily taken into account because they are relatively weightless	8
4244868245	Isotope	Atoms of an element with different number of neutrons; these have same chemical properties but different masses and may be radioactive	9
4244871018	Valence Electrons	Electrons in the outermost energy level of an atom; the key to chemical bonds	10
4244872183	Octet Rule	Rule that atoms tend to completely fill their outermost energy level	11
4244874091	Half-life	Amount of time it takes for half of a substance to decay	12
4244877731	Ion	Atoms in which the number of electrons is not the same as the number of protons and are either positive or negative	13
4244878774	Anion	A negatively charged ion that has more electrons than protons	14
4244880043	Cation	A positively charged ion that has more protons than electrons	15
4244880796	Ionic Bond	Chemical bond forming between oppositely charged ions (cation + anion)	16
4244883297	Molecule	Group of atoms held together by energy in a stable association (chemical bond)	17
4244884410	Compound	When a molecule contains more than one element	18
4244885204	Covalent Bond	Chemical bond forming when two atoms share one or more pairs of valence electrons -single, double or triple bonds (increase in strength)	19
4244926017	Increasing Rate of Reaction	More concentration = more collisions Higher temperature = more collisions Catalysts = facilitate chemical reactions	20
4244887679	Polar Bond	In covalent bonds, when there is an unequal distribution of charge and so there is partial negative and partial positive charge	21
4244890451	Electronegativity	The tendency of an ion to take an electron -increases up periodic table and to the right -different electronegativity creates polar covalent bonds	22
4244892299	Hydrogen Bond	A weak chemical association with hydrogen in polar covalent bonds	23
4244894877	Hydrophobic	Substances that do not combine or are not soluble in water	24
4244896529	Hydrophilic	Substances that combine or are soluble in water	25
4244897488	Cohesion	When a molecule is attraction to one another because of polarity (hydrogen bonds) -water -causes surface tension	26
4244900486	Adhesion	When a polar molecule is attracted to other polar molecules -water -causes capillary action -things that get "wet"	27
4244905285	Surface Tension	Tautness of the surface of a liquid caused by the cohesion of molecules -water strider walking on water	28
4244907516	Capillary Action	Tendency of a liquid in a tube to rise above the surrounding liquid -transpiration in plants	29
4244908318	Specific Heat	Amount of heat that must be absorbed or lost by 1 gram of a substance to change its temperature by 1 degree celsius -water has high specific heat which is why cities by water bodies are cool i.e. San Francisco	30
4244922316	Heat of Vaporization	Amount of energy required to change 1 gram of a substance from liquid to gas -water has a high heat of vaporization which is why sweating helps cool organisms	31
4244967660	Ice Water	Solid water is less dense than liquid water -why lake freezes from top and liquid water on bottom for organisms to live	32
4244969386	Aqueous Solution	A solution where the solvent is water	33
4244970276	Solute	Molecule being dissolved in a solution	34
4244970916	Solvent	Median in which one or more solutes are dissolved in -water is universal solvent	35
4244974466	Hydration Shell	Cloud of water molecules that forms around ions or polar molecules to prevent them from bonding; dissolving	36
4244977610	Hydrophobic Exclusion	Nonpolar molecules (hydrophobic) are forced to cluster together in presence of water -important for structure of proteins, DNA and cell membranes	37
4244981989	Mole	Unit of something -weight of substance in grams of atomic masses -6.02x10^23 particles in a mole (Avogadro's Number) -22.4 Liters of gas at STP (0°C or 273K @ 1atm or 101kPa)	38
4244993165	Molarity	(M) Moles of solute per liter of solvent (moles/L)	39
4244995475	Acid	Any substance that dissociates in water to increase the hydrogen ion concentration and has pH lower than 7	40
4244996500	Hydrogen Ion	Proton that dissociates from a water molecule to be a cation	41
4244997387	Base	Any substance that dissociates in water to absorb and decrease the H+ concentration and has pH higher than 7	42
4244999307	Hydroxide Ion	Ion left behind after the hydrogen atom dissociates from a water molecule; anion	43
4245000487	pH	"Partial Hydrogen", the negative logarithm of the hydrogen ion concentration of a solution (pH=-log[H+])	44
4245003826	Buffer	Substance that resists changes in pH -Carbonic acid (H2CO3) and bicarbonate (HCO3-) [H20 + CO2 → H2CO3 → HCO3 + H+] -for controlling blood pH (around 7.4) -blood acidosis = pH 7.1 or lower -blood alkalosis = pH 7.7 or higher	45