CEM 142 EXAM 2 QUESTIONS AND
ANSWERS 2026 VERIFIED.
7.1. Explain, using a molecular level explanation, the difference between a chemical change and
a phase change. Describe the evidence you would use to support your explanation. - ANS
chemical change - ANS A change in matter that produces one or more new substances
phase change - ANS a change from one state (solid or liquid or gas) to another without a
change in chemical composition
7.2. Identify the molecular structural features that lead to acidic and basic properties in a
molecule. Explain why these features are important. - ANS Acids-proton is donated, h+
beginning
bases- accepts a proton, oh ending
7.3. Know common strong acids (HCl, HBr, HI, HNO3, H2SO4) and bases (group I or II metals with
a hydroxide ion such as, NaOH and KOH). - ANS
7.4. Use the words strong, weak, dilute, and concentrated appropriately. - ANS if strong will
completely separate. if weak won't completely separate. dilute has all separated just not as
many molecules as concentrated would
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,7.5. Predict and explain relative strengths of a range of related acids (or bases) using
thermodynamic or electronegativity arguments. - ANS acids- increase to the left and down,
unless H is attached to something else like hclo>hio find out which is more electronegative
7.6. Explain how the progression of Arrhenius, Bronsted-Lowry, and Lewis acid-base theories
build on each other. - ANS arrhenius-This states that an acid dissolves in water to give an
H+(proton) proton while a base dissolves in water to give -OH (hydroxide). Ignores the role of
water.
Bronsted-Lowry - ANS This states that an acid is a proton donor while a base is a proton
acceptor
7.7. Predict the products of acid base reactions based on the relative strengths of the acids and
bases. - ANS
7.8. Predict the extent of acid-base reactions (more products or more reactants) based on
relative acid/base strength. - ANS
7.9. Use curved arrow notation to predict the products of Lewis acid-base reaction and simple
nucleophilic attacks at electrophilic carbons (for example, N-methylations). - ANS
7.10. Calculate pH from given concentration of strong (i.e. completely ionized) acids or bases. -
ANS
7.11. Use pH to calculate [H3O+] or [-OH]. - ANS
7.12. Use pH of solutions of the same concentration to determine relative strengths of acids and
bases. - ANS
7.13. Identify and explain why acid base reactions are different from redox reactions. - ANS
7.14. Recognize redox reactions by looking for changes in oxidation numbers. - ANS
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, draw HCL in the liquid and gas state - ANS in notebook
Do these solutions conduct electricity?
sugar(ag)
NaCl (aq)
HCl (aq) - ANS 1.)no, no ions present
2.)yes, overcoming ion-ion, forming ion-dipole
3.)yes
is dissolving a solute in a solvent a chemical reaction? - ANS sometimes
what are chemical reactions? - ANS the making and breaking of chemical bonds. Examples
are 2H2+ O2-->2H2O
What is a phase change? - ANS a reversible physical change that occurs when a substance
changes from one state of matter to another
is a phase change a chemical reaction? - ANS no
is formation of a solution a chemical reaction? - ANS sometimes
chemical reactions - ANS involve arrangement of atoms
atoms conserved
@COPYRIGHT ALL RIGHTS RESERVED PAGE 3 OF 18
ANSWERS 2026 VERIFIED.
7.1. Explain, using a molecular level explanation, the difference between a chemical change and
a phase change. Describe the evidence you would use to support your explanation. - ANS
chemical change - ANS A change in matter that produces one or more new substances
phase change - ANS a change from one state (solid or liquid or gas) to another without a
change in chemical composition
7.2. Identify the molecular structural features that lead to acidic and basic properties in a
molecule. Explain why these features are important. - ANS Acids-proton is donated, h+
beginning
bases- accepts a proton, oh ending
7.3. Know common strong acids (HCl, HBr, HI, HNO3, H2SO4) and bases (group I or II metals with
a hydroxide ion such as, NaOH and KOH). - ANS
7.4. Use the words strong, weak, dilute, and concentrated appropriately. - ANS if strong will
completely separate. if weak won't completely separate. dilute has all separated just not as
many molecules as concentrated would
@COPYRIGHT ALL RIGHTS RESERVED PAGE 1 OF 18
,7.5. Predict and explain relative strengths of a range of related acids (or bases) using
thermodynamic or electronegativity arguments. - ANS acids- increase to the left and down,
unless H is attached to something else like hclo>hio find out which is more electronegative
7.6. Explain how the progression of Arrhenius, Bronsted-Lowry, and Lewis acid-base theories
build on each other. - ANS arrhenius-This states that an acid dissolves in water to give an
H+(proton) proton while a base dissolves in water to give -OH (hydroxide). Ignores the role of
water.
Bronsted-Lowry - ANS This states that an acid is a proton donor while a base is a proton
acceptor
7.7. Predict the products of acid base reactions based on the relative strengths of the acids and
bases. - ANS
7.8. Predict the extent of acid-base reactions (more products or more reactants) based on
relative acid/base strength. - ANS
7.9. Use curved arrow notation to predict the products of Lewis acid-base reaction and simple
nucleophilic attacks at electrophilic carbons (for example, N-methylations). - ANS
7.10. Calculate pH from given concentration of strong (i.e. completely ionized) acids or bases. -
ANS
7.11. Use pH to calculate [H3O+] or [-OH]. - ANS
7.12. Use pH of solutions of the same concentration to determine relative strengths of acids and
bases. - ANS
7.13. Identify and explain why acid base reactions are different from redox reactions. - ANS
7.14. Recognize redox reactions by looking for changes in oxidation numbers. - ANS
@COPYRIGHT ALL RIGHTS RESERVED PAGE 2 OF 18
, draw HCL in the liquid and gas state - ANS in notebook
Do these solutions conduct electricity?
sugar(ag)
NaCl (aq)
HCl (aq) - ANS 1.)no, no ions present
2.)yes, overcoming ion-ion, forming ion-dipole
3.)yes
is dissolving a solute in a solvent a chemical reaction? - ANS sometimes
what are chemical reactions? - ANS the making and breaking of chemical bonds. Examples
are 2H2+ O2-->2H2O
What is a phase change? - ANS a reversible physical change that occurs when a substance
changes from one state of matter to another
is a phase change a chemical reaction? - ANS no
is formation of a solution a chemical reaction? - ANS sometimes
chemical reactions - ANS involve arrangement of atoms
atoms conserved
@COPYRIGHT ALL RIGHTS RESERVED PAGE 3 OF 18
