# Final exam review

 Hypothesis
 An unverified explanation of a natural phenomenon
 Scientific Method
 The process of making observations, proposing a hypothesis, testing the hypothesis, and developing a theory that explains a natural event
 Theory
 An explanation of an observation that has been validated by experiments that support a hypothesis
 2.2
 1 kg = ____ lb
 454
 1 lb = ____ g
 946
 _____ mL = 1 qt
 1.06
 1 L = ____ qt
 2.54
 _____ cm = 1 in.
 39.4
 1 m = ____ in.
 0.621
 1 km = ____ miles
 Mass Volume
 The formula for Density is
 4.184
 1 cal = _______ J
 TFº= 1.8(TC°) + 32
 The formula to change Celsius to Fº is
 TK = TC + 273
 The formula to change Celsius to Kelvin is
 heat cal(or J) grams x (Change in Temp Cº)
 Specific Heat (SH) =
 mass x ΔT x SH
 Heat =
 1 kcal or 4.184kJ
 1 Cal =
 pure substances
 A _______ is matter that has a definite composition. There are two kinds: elements and compounds
 element
 An ______ is the simplest pure substance b/c it is composed of only one kind of material. Ex. Si, Fe, Al
 compound
 A ______ is also a pure substance, but it consists of two or more elements always in the same proportion.
 mixture
 In a _______ two or more substances are physically _____, but not chemically combined
 homogeneous
 In a ________ mixture, also called a solution, the composition is uniform throughout the sample. Ex. air, saltwater
 Liquid
 Has a definite volume but not a definite shape, particles move in random directions but are sufficiently attracted to each other to matin def. vol. not a rigid structure
 Solid
 Has a definite shape and volume, strong attractive forces hold particles close together
 Gas
 Does not have a def. shape or volume. The particles are far apart, have little attraction, move at high speeds, taking shape/vol. of container
 Heating Curve
 [image]
 Cooling Curve
 [image]
 Group 1 – alkali metals Group 2 – Alkaline earth metals Middle Transition elements Group 7 – Halogens Group 8 – Noble gases
 [image]
 Green – Metals Blue – Metalliods Yellow – Nonmetals
 [image]
 Atomic number
 Is equal to the number of protons in the nucleus of an atom, is used to identify and define each element
 Mass number
 number of protons + number of neutrons
 Isotopes
 are toms of the same element that have diff. number of neutrons
 atomic mass
 the weighed average of the ______ of all the naturally occuring isotopes of that element
 Atomic size
 [image]
 Ionization Energy
 [image]
 Half life
 of a radioisotope is the time for a radiation level to decrease (decay) to one-half of the original value
 Alpha Decay
 4 He                                           2 mass number 4 less atomic number 2 less shielding: paper, clothing
 Beta Decay β
 0 e -1 Mass # – same Atomic # – +1 shielding: Heavy clothing, lab coats, gloves
 Metal
 _____ atoms lose all their valence electrons from their outermost energy level
 increases
 The size of nonmetal atoms _______ because they gain electrons in the outermost energy level.
 Ionic bond
 Loss and gain of electrons
 Covalent bond
 Sharing of electrons
 Nonpolar
 A covalent bond between atoms with identical or very similar electronegativity values is ________
 Polar
 Atoms with diff. electronegativity values. When electrons are shared unequally, the bond is _____
 dipole
 A polar covalent bond that has a separation of charges is called a  δ+ and δ – , δ+ and δ–
 Nonpolar Polar Ionic
 Shared equally H-H 0 – 0.4 – Shared unequally H δ+-Br δ– 0.5 – 1.7 Electron transfer Na+ Cl – 1.8 +
 VSEPR theory Valence-Shell Electron-Pair Repulsion
 indicates that the electron groups will move as far apart as possible to reduce the repulsion between their negative charges
 Nonpolar
 Molecules with two or more polar bonds can also be ______ if the polar bonds have a symmetrical arrangement in the molecule
 polar
 In a _______ molecule, one end of the molecule is more negatively charged than another end. Occurs when the polar bonds dont cancel each other
 nonpolar
 a _______ molecule occurs when the polar bonds or dipoles in a molecule cancel each other
 Strongest to weakest
 Arranged from…. Ionic bonds, hydrogen bonds, dipole-dipole attractions, dispersion forces
 bottom of the arrow weakest, top of the arrow strongest
 [image]
 Oxidation
 is defined as the loss of electrons
 Reduction
 defined as the gain of electrons
 REDOX
 electrons are transferred from one substance to another
 oxidized reduced
 In terms of oxidation and reduction atoms of a metal are ________, and atoms of a nonmetal are _______
 increases decreases
 losing electrons _______ charge gaining electrons _______ charge
 6.02 x 1023 1 mole
 Avogadro’s number is______ is used as a conversion between the ;moles of a substance and number of particles it contains
 mass volume ;
 Percent concentration is
 Soluble
 Alkali metals, NH4+1, NO3-1, Cl, Br, I, SO4-2
 NOT SOLUBLE
 Ag, Pb, Hg, (Ca, Sr, Br, P)unless + ion is larger OH-1, CO3-2, S-2, PO4-3;(unless with alkali metals)
x

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