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CHEM 120 FINAL EXAM REVIEW|104 QUESTIONS
AND ANSWERS|UPDATED 2025|A+ GRADED
significant figures a digit that is either reliably known or closely estimated Significant Figure Rules
- All non-zero digits are always significant
- Zeroes between non-zero digits are always significant
- Zeroes to left of first non-zero digit (either before or after decimal point) are never significant
- Zeroes to the right of last non-zero digit a. after decimal point are always significant b. which are before decimal point are not significant conversion factor relationship between two quantities expressed as a fraction dimensional analysis
conversion of a measurement in one unit into another by the use of conversion factors True T/F: number of protons never changes according to periodic table number of protons atomic number=_______________________ number of neutrons mass number=_______________________ isotopes atoms with same number of protons (same electron) but different number of neutrons atomic mass
ion atom that has an electrostatic charge cation positively charged atom anion negatively charged atom formula unit simplest whole number ratio of ions in ionic compound polyatomic ion groups of covalently-bonded atoms that have an overall charge physical change change in a substance that does not change its composition
extensive physical properties properties that depend on the amount of matter present (ex-mass, volume) intensive physical properties properties that do not depend on the amount of matter present (ex- color, clarity, physical state, melting/boiling points, density) chemical change the transformation of a substance into a different substance (ex-rusting iron, burning coal, baking soda reacting with vinegar density the ratio of a substance's mass to its volume D=m/V mixture
-cannot be separated by physical methods homogeneous mixtures -NOT pure substance -2+ substances physically combined -final mix has the properties of each of the components that make it up -can be separated by physical means acid molecular compound made by combining H+ ions with a monoatomic or polyatomic ion naming -If the anion name ends in "-ite," the acid name ends in "-ous" -If the anion name ends in "-ate," the acid name ends in "-ic" mole the number of atoms represented by atomic mass of an element
molar mass the atomic mass of the element expressed in grams formula weight mass of one molecule of formula unit of a compound (in amu) mole ratio relationship between the number of moles of an element and a mole of the compound containing it empirical formula simplest whole-number ratio of atoms in a compound law of conservation of mass mass can neither be created nor destroyed
single replacement one metal + one ionic compound as reactants double replacement 2 ionic compounds as reactants activity series a list of metals/H2 in decreasing order of their ability to replace metal/H+ ions in aqueous solution oxidation state the charge that an atom would have if all the bonded electrons were transferred to the more "electronegative" atom oxidized When an element loses electrons, it is being __________.
reduced When an element gains electrons it is being __________. oxidizing agent the species in a reaction that causes another one to be oxidized reducing agent the species in a reaction that causes another one to be reduced redox reaction a reaction involving an exchange (transfer) of electrons subshells different types or shapes of orbitals within a single electron shell 1st shell
the assignment of all of the electrons in an atom into specific shells and subshells orbital diagram representation of the orbitals in a subshell as boxes and the electrons in them as arrows Hund's Rule electrons occupy separate orbitals in the same subshell with parallel spins (electrons repel each other) Lewis structure a combination of Lewis dot, showing:
- the order and arrangement of atoms in a molecule
- the valence electrons of each atom molecular geometry geometry formed by only the bonded atoms around the central atom.... where the lone pairs are invisible
stoichiometric If you have exactly the amounts of reactants to react completely with nothing leftover, the mixture is called _______________. limiting reactants the reactant that can produce the least amount of product or limits how much product can be made excess reactant the reactant(s) that is/are leftover (in excess) after the limiting reactant is used up completely percent yield the ratio of the amount of product actually made to the amount of product that could have been made under an ideal situation theoretical yield
ideal gas law the volume of a gas is related to pressure, temperature, and number of moles; PV=nRT
R=___________ intermolecular forces interaction between the molecules of a compound london forces electrostatic forces between molecules that result from instantanenous (temporary) dipoles; WEAKEST interaction & present in ALL molecular compounds dipole-dipole POLAR molecules have an overall, permanent dipole
dipole-dipole attractions the attraction of the negative end of a polar molecule with the positive end of another polar molecule; INTERMEDIATE strength Hydrogen bonding in molecules with N, O, F bonded to H; STRONGEST intermolecular interaction; VERY POLAR % by mass = (mass solute/mass solute + mass solvent) * 100% % by mass =(mass solute/mass solution) * 100% solubility
colligative property a property of a substance that depends on how much of a solute is added to it, NOT on what solute is added colligative properties the following are________________________:
- vapor pressure
- boiling point
- freezing point
- osmotic pressure osmotic pressure if pure water and a solution are separated by a semipermeable membrane, water will form from the solvent side to the solution side freezing point adding a solute decreases the freezing point
boiling point adding a solute increases the boiling point Bronsted-Lowry Acids donating and accepting H+ conjugate base the base that remains after an acid gives up it's proton conjugate acid the acid that is formed when a base has accepted to a proton pH expressing how acidic a solution is using its H3O+ or OH- pOH=-log(OH-) calculating pOH
