CHEM 1011 ACTUAL 2026 EXAM QUESTIONS AND
SOLUTIONS RATED A+
✔✔titration - ✔✔a measured amount of a solution of unknown concentration is added to
a known volume of a second solution until the reaction between them is just complete
✔✔Phenolpthalein - ✔✔ph indicator taht turns bright pink at a basic pH of 8.2 and
higher
✔✔stoichiometric equivalence point - ✔✔the point at which chemically equivalent
quantites of the acid and abse are rpesent; this is determine by using an indiciator
which changes color in the presence of acids/bases based on pH of a solution
✔✔hard water - ✔✔wter that contains high levels of dissolved minerals in the form of
metallic ions
✔✔ions that contribute to hardiness of water - ✔✔Ca, Mg HCO3-, CO3^2- (most
common mineral in hard water is calcium)
** hardiness is reproted in concentraion of CaCO3
✔✔how is hard water formed - ✔✔formed as water flows over and through rocks and
minerals like limestone; water is a polar molecule and acts as a solvent to many solutes
(especially ionic compounds like CaCO3)
** water hardiness varies by location (depending on limestone)
✔✔4 classifications of water hardiness - ✔✔Soft (0-60)
Moderately Hard (61-120)
Hard (120-180)
Very hard (>180)
✔✔how are concentrations of CaCO3 determined in water - ✔✔via titration with EDTA,
which is a chelating agent = has a high affinity oof metal ions; performed with indiciator
Eriochrome Black T (EBT)
✔✔What happens when EBT is added to hard water? - ✔✔it forms a complex with the
metal ions and turns a palem purple-pink color
✔✔What occurs as EDTA is titrated into the hard water - ✔✔the metal ions are released
from the EBT and instead form a complex with EDTA since it has a higher affinity for
metallic ions
**when EBT is completely released from the metal ions, it changes to a blue-gray color
indicating titration is complete
, ✔✔oxidation-reduction (redox) reaction - ✔✔a chemical reactions taht occurs when
electrons are transferred from one reactant to another
**during a reaction, electrons are neither created nor destroyed=> just transferred
among atoms
✔✔oxidation number - ✔✔(oxidation state) the change an electron would have if
electrons were completely transferred
✔✔oxidation - ✔✔the LOSS of electrons by a substance undergoing a chemcial
reaction; during this time, the oxidation number of the element INCREASES and
becomes more positive
✔✔reduction - ✔✔GAIN of electrons by a substance undergoing a chemcial reaction;
during this time, the oxidation numbr of the element DECREASES and becomes more
negative
✔✔reducing agent - ✔✔the electron donor (because it is reducing the other substance)
✔✔oxidizing agent - ✔✔the electron acceptor (because it oxidizes the other substance)
✔✔single displacement reaction - ✔✔chemical reaction in which one element replaces
another element in a compound and part of the compount is released to become a free
element
Ex. Fe + CuSO4 ---> FeSO4 + Cu
✔✔spectator ion - ✔✔an ion that appears on both sides of an equation and is not
directly involved in the reaction; it is neither oxidized or reduced
✔✔Activity series - ✔✔a list of elements organized according to the ease with which the
elements undergo certain chemical reactions
-ordered from most active (easily oxidized) to least active (low ease of oxidation)
✔✔Electrochemistry - ✔✔the study of electrical aspects of chemical reactions
concerned with two processes: 1) the generation of an electrical current resulting from a
spontaneous chemical reaction & 2) the use of an electrical current to prodce a
chemical reaction
✔✔oxidation half-reaction - ✔✔process involving the reactant that electrons to form a
product with a higher oxidation state
✔✔reduction half-reaction - ✔✔the other reactant accepts electrons to form a product
with a lower oxidation state
SOLUTIONS RATED A+
✔✔titration - ✔✔a measured amount of a solution of unknown concentration is added to
a known volume of a second solution until the reaction between them is just complete
✔✔Phenolpthalein - ✔✔ph indicator taht turns bright pink at a basic pH of 8.2 and
higher
✔✔stoichiometric equivalence point - ✔✔the point at which chemically equivalent
quantites of the acid and abse are rpesent; this is determine by using an indiciator
which changes color in the presence of acids/bases based on pH of a solution
✔✔hard water - ✔✔wter that contains high levels of dissolved minerals in the form of
metallic ions
✔✔ions that contribute to hardiness of water - ✔✔Ca, Mg HCO3-, CO3^2- (most
common mineral in hard water is calcium)
** hardiness is reproted in concentraion of CaCO3
✔✔how is hard water formed - ✔✔formed as water flows over and through rocks and
minerals like limestone; water is a polar molecule and acts as a solvent to many solutes
(especially ionic compounds like CaCO3)
** water hardiness varies by location (depending on limestone)
✔✔4 classifications of water hardiness - ✔✔Soft (0-60)
Moderately Hard (61-120)
Hard (120-180)
Very hard (>180)
✔✔how are concentrations of CaCO3 determined in water - ✔✔via titration with EDTA,
which is a chelating agent = has a high affinity oof metal ions; performed with indiciator
Eriochrome Black T (EBT)
✔✔What happens when EBT is added to hard water? - ✔✔it forms a complex with the
metal ions and turns a palem purple-pink color
✔✔What occurs as EDTA is titrated into the hard water - ✔✔the metal ions are released
from the EBT and instead form a complex with EDTA since it has a higher affinity for
metallic ions
**when EBT is completely released from the metal ions, it changes to a blue-gray color
indicating titration is complete
, ✔✔oxidation-reduction (redox) reaction - ✔✔a chemical reactions taht occurs when
electrons are transferred from one reactant to another
**during a reaction, electrons are neither created nor destroyed=> just transferred
among atoms
✔✔oxidation number - ✔✔(oxidation state) the change an electron would have if
electrons were completely transferred
✔✔oxidation - ✔✔the LOSS of electrons by a substance undergoing a chemcial
reaction; during this time, the oxidation number of the element INCREASES and
becomes more positive
✔✔reduction - ✔✔GAIN of electrons by a substance undergoing a chemcial reaction;
during this time, the oxidation numbr of the element DECREASES and becomes more
negative
✔✔reducing agent - ✔✔the electron donor (because it is reducing the other substance)
✔✔oxidizing agent - ✔✔the electron acceptor (because it oxidizes the other substance)
✔✔single displacement reaction - ✔✔chemical reaction in which one element replaces
another element in a compound and part of the compount is released to become a free
element
Ex. Fe + CuSO4 ---> FeSO4 + Cu
✔✔spectator ion - ✔✔an ion that appears on both sides of an equation and is not
directly involved in the reaction; it is neither oxidized or reduced
✔✔Activity series - ✔✔a list of elements organized according to the ease with which the
elements undergo certain chemical reactions
-ordered from most active (easily oxidized) to least active (low ease of oxidation)
✔✔Electrochemistry - ✔✔the study of electrical aspects of chemical reactions
concerned with two processes: 1) the generation of an electrical current resulting from a
spontaneous chemical reaction & 2) the use of an electrical current to prodce a
chemical reaction
✔✔oxidation half-reaction - ✔✔process involving the reactant that electrons to form a
product with a higher oxidation state
✔✔reduction half-reaction - ✔✔the other reactant accepts electrons to form a product
with a lower oxidation state
