test 1

• a law is a mathematical expression that summarizes a pattern found in observations and a theory is the explanation of the expression based on experiments
• theories describe why/how a particular situation occurs, or the underlying reasons for them
• laws will describe what will occur in a particular situation; they summarize a series of related observations
• the kinetic-molecular theory of matter states that as matter gains energy, its temperature and kinetic energy increase; as kinetic energy increases, matter transforms from solid to liquid to gas
• in a solid, the attractive forces between the particles are stronger than the kinetic energy of the individual particles
• in liquids, the kinetic energy of the individual particles have begun to overcome their attractive forces to other particles
• in a gas, the individual particles kinetic energy has completely overcome their attractive forces to other particles
• a chemical change will always result in a change in composition
• in liquid and gas mixtures, substances that are less dense in the mixture will float on top of substances that are denser
• 1 pound is equal to 453.59 grams
• 1 meter is equal to 3.281 feet
• 1 pound is equal to 16 ounces
• 1 mile is equal to 5280 feet
• 1 inch is equal to 2.54 cm
• 1 mile is 1760 yards
• on the celcius scale water freezes at 0 and boils at 100
• on the fahrenheit scale water freezes at 32 and boils at 212
• on the Kelvin scale water freezes at 273 K and boils at 373 K
• the diatomic elements are H, N, O, F, Cl, Br, and I
• the density formula is mass (g) / volume (mL or cm^3)
• the law of conservation of mass states that energy cannot be created nor destroyed
• the law of constant compositions (definite proportions) states that the ratio of the masses of the elements in a compound is always the same
• daltons atomic theory states atoms are the smallest unit of an element, atoms are neither created nor destroyed during a chemical change, an element consists of only one type of atom, and a compound consists of atoms of two or more elements combined in a small, whole-number ratio
• not all of dalton's atomic theory holds true today: atoms are made up of even smaller units and all atoms are not necessarily identical
• ernest rutherford - gold foil experiment - determined structure of the atom (nucleus model); disproves the plum pudding model
• the number of protons in an atom corresponds to the atomic number of the atom, which identifies an atom as a particular type of element
• mass number of an element is given by adding together the number of protons and neutrons that are present in an element
• the number of electrons and protons in an atom will always be equal for neutral atoms
• jj thomas - cathode-ray tube - discovered charge-to-mass ratio of an electron - made plum pudding model
• robert millikan - oil drop experiment - determined charge and mass of an electron
• atoms become cations when they lose electrons to become positively charged ions
• atoms become anions when they gain electrons to become negatively charged ions
• if an element loses a proton it becomes a different element
• covalent bonding leads to the formation of molecular compounds
• ionic bonding leads to the formation of ionic compounds
• in an ionic compound the metal loses electrons (becoming a cation) and the non-metal gains electrons (becoming an anion)
• polyatomic ions combine with other ions to form ionic compounds but the actual polyatomic ion is held together by covalent bonding
• the most common transition metals that only form one charge and do not require roman numerals: silver (Ag), zinc (Zn), and cadmium (Cd)
• singular atoms are named by using the prefix of the element's name, followed by the suffix "-ide"
• polyatomic ions as cations or anions retain their name with no change