CHEM 121 FINAL PAPER 2025/2026 QUESTIONS WITH
ANSWERS GRADED A+
✔✔Molecular Formula vs Empirical Formula - ✔✔molecular = exact numbers of each
element in a molecule (Benzene: C6H6)
emperical = the ratio of each element to the others (6C- +6 H+)
✔✔actual yield vs theoretical yield - ✔✔actual: the amount of product obtained when
reaction is done in a lab
theoretical: maximum amount of product that can be obtained
✔✔Percent yield - ✔✔actual yield/theoretical yield x 100
how well a reaction is working
✔✔solute vs solvent vs solution - ✔✔solute is the thing thats being dissolved,
solvent does the dissolving,
solution is the mixture of the solute and the solvent
✔✔water can dissolve non-ionic compounds as long as... - ✔✔they are polar
non-polar are insoluble
✔✔3 types of chemical reactions - ✔✔precipitation, acid-base, oxidation-reduction
✔✔Arrhenius concept - ✔✔acids produce hydrogen ions in aqueous solution, while
bases produce hydroxide ions
✔✔oxidation-reduction reaction - ✔✔any chemical change in which one species is
oxidized (loses electrons) and another species is reduced (gains electrons); also called
redox reaction
✔✔Rules for assigning oxidation states - ✔✔1) Standard state is 0
2) Sum of oxidation states in a compound must be 0 or the ion's charge
3) Group 1 has +1 and group 2 has +2
4) Fluorine has -1
, 5) Hydrogen has +1 or 0 when bound to carbon (can also be -1 if less electronegative
than carbon)
6) Oxygen has -2 (however it is -1 when bound to peroxides H2O2)
7) Halogens have -1 and oxygen family has -2.
*oxidation states do not have to be whole numbers
✔✔oxidation vs reduction - ✔✔Oxidation is loss of electrons
Reduction is gain of electrons
✔✔Balancing redox reactions - ✔✔1. Separate the two half reactions
2. Balance the atoms of each half reaction(may have to add H2O or H)
3.Balance the electrons of each half reaction
4.Combine the half reactions
5.Confirm mass and charge are equal
✔✔Strong electrolytes are - ✔✔strong acids, strong bases, soluble ionic salts
substances that are completely ionized in aqueous solution
✔✔weak electrolytes - ✔✔weak acids and weak bases
substances that are only partially ionized in solution
✔✔Units of Pressure - ✔✔1 atm = 100 kPa = 760 torr = 760 mmHg
✔✔Manometer - ✔✔instrument to measure pressure
✔✔Boyle's Law - ✔✔A principle that describes the relationship between the pressure
and volume of a gas at constant temperature
P1V1=P2V2
P increases, V decreases
✔✔Charles's Law - ✔✔A principle that describes the relationship between the
temperature and volume of a gas at constant pressure
ANSWERS GRADED A+
✔✔Molecular Formula vs Empirical Formula - ✔✔molecular = exact numbers of each
element in a molecule (Benzene: C6H6)
emperical = the ratio of each element to the others (6C- +6 H+)
✔✔actual yield vs theoretical yield - ✔✔actual: the amount of product obtained when
reaction is done in a lab
theoretical: maximum amount of product that can be obtained
✔✔Percent yield - ✔✔actual yield/theoretical yield x 100
how well a reaction is working
✔✔solute vs solvent vs solution - ✔✔solute is the thing thats being dissolved,
solvent does the dissolving,
solution is the mixture of the solute and the solvent
✔✔water can dissolve non-ionic compounds as long as... - ✔✔they are polar
non-polar are insoluble
✔✔3 types of chemical reactions - ✔✔precipitation, acid-base, oxidation-reduction
✔✔Arrhenius concept - ✔✔acids produce hydrogen ions in aqueous solution, while
bases produce hydroxide ions
✔✔oxidation-reduction reaction - ✔✔any chemical change in which one species is
oxidized (loses electrons) and another species is reduced (gains electrons); also called
redox reaction
✔✔Rules for assigning oxidation states - ✔✔1) Standard state is 0
2) Sum of oxidation states in a compound must be 0 or the ion's charge
3) Group 1 has +1 and group 2 has +2
4) Fluorine has -1
, 5) Hydrogen has +1 or 0 when bound to carbon (can also be -1 if less electronegative
than carbon)
6) Oxygen has -2 (however it is -1 when bound to peroxides H2O2)
7) Halogens have -1 and oxygen family has -2.
*oxidation states do not have to be whole numbers
✔✔oxidation vs reduction - ✔✔Oxidation is loss of electrons
Reduction is gain of electrons
✔✔Balancing redox reactions - ✔✔1. Separate the two half reactions
2. Balance the atoms of each half reaction(may have to add H2O or H)
3.Balance the electrons of each half reaction
4.Combine the half reactions
5.Confirm mass and charge are equal
✔✔Strong electrolytes are - ✔✔strong acids, strong bases, soluble ionic salts
substances that are completely ionized in aqueous solution
✔✔weak electrolytes - ✔✔weak acids and weak bases
substances that are only partially ionized in solution
✔✔Units of Pressure - ✔✔1 atm = 100 kPa = 760 torr = 760 mmHg
✔✔Manometer - ✔✔instrument to measure pressure
✔✔Boyle's Law - ✔✔A principle that describes the relationship between the pressure
and volume of a gas at constant temperature
P1V1=P2V2
P increases, V decreases
✔✔Charles's Law - ✔✔A principle that describes the relationship between the
temperature and volume of a gas at constant pressure
