Organic Chemistry ACS Exam Set 2025 Compprehensive
Questions and Answers Latest 2025[Answered}
state the similarities and differences between the atomic structure of isotopes of
the same element - ans -similarities - same number of electrons and protons,
differences - atomic mass
what are the reagents and conditions needed to convert an alkene into a
saturated hydrocarbon? - ans -hydrogen under reflux and a nickel catalyst
write the ionic equation for the reaction between aqueous lead nitrate and
aqueous potassium iodide ( Pb(NO3)2(aq) + 2KI(aq) --> PbI2(s) + 2KNO3(aq)) - ans
-Pb 2+ (aq) + 2I- (aq) --> PbI2 (s)
write an equation including state symbols to represent the second ionization
energy of strontium - ans -Sr+ (g) --> Sr2+ (g) + e-
explain the differences in the melting points of phosphorus and chlorine - ans -
phosphorus has more electrons, so stronger London forces, so more energy is
required to break the intermolecular forces
describe the bonding in magnesium and silicon. include the names of the particles
and describe the forces between the particles in the structures - ans -magnesium
has metallic bonds, which contains cations and delocalised electrons. silicon has
covalent bonds between atoms
describe one difference between the sigma bond and the pi bond - ans -pi bonds
have sideways overlap, sigma bonds have head on overlap of orbitals
explain in terms of bond breaking and bond making, why the enthalpy change of
formation of NO is endothermic - ans -more energy is required for bond breaking
than is released by bond making
write 2 equations to show how NO radicals catalyse the breakdown of ozone - ans
-*NO + O3 --> *NO2 + O2
NO2 + O2 --> *NO + O2
, compare the electrical conductivities of solid and aqueous barium chloride - ans -
barium chloride does not conduct electricity when solid because it has ions that
are in a fixed position. barium chloride conducts when in aqueous solutions
because it has mobile ions
describe the use of aqueous barium chloride in qualitative analysis - ans -it is used
to test for sulfate, and a white precipitate forms
what is the electron configuration of a nitride ion? - ans -1s2 2s2 2p6
describe the oxidation reactions of butan-1-ol forming an aldehyde and a
carboxylic acid - ans -forming an aldehyde requires acid and dichromate, with
heating under distillation. the product formed is butanal. forming a carboxylic
acid requires acid and dichromate, with heating under reflux. the product formed
is butanoic acid. distillation apparatus contain a condenser with water flow, and a
collection of the organic product.
what are the reagents and conditions to form cyclohexene from
bromocyclohexene - ans -acid catalyst and heat
explain why group 2 elements are reducing agents - ans -group 2 metals add
electrons to other species
state and explain the trend in alkalinity of the solution formed when group 2
oxides are added to water - ans -group 2 oxides react with water forming the
metal hydroxide. hydroxide ions in solution cause alkalinity. down group 2, the
solubility of the metal hydroxide increases, increasing the pH and alkalinity
state and explain the trend in boiling points of the halogens fluorine to iodine -
ans -boiling point increases due to the increase in electrons down the group. this
increases the strength of the London forces and more energy is needed to break
the intermolecular forces
explain why it is important to carry out the carbonate test before carrying out the
sulfate test on an unknown chemical - ans -dilute nitric acid reacts with carbonate
ions ad no precipitate of barium carbonate will then form
Questions and Answers Latest 2025[Answered}
state the similarities and differences between the atomic structure of isotopes of
the same element - ans -similarities - same number of electrons and protons,
differences - atomic mass
what are the reagents and conditions needed to convert an alkene into a
saturated hydrocarbon? - ans -hydrogen under reflux and a nickel catalyst
write the ionic equation for the reaction between aqueous lead nitrate and
aqueous potassium iodide ( Pb(NO3)2(aq) + 2KI(aq) --> PbI2(s) + 2KNO3(aq)) - ans
-Pb 2+ (aq) + 2I- (aq) --> PbI2 (s)
write an equation including state symbols to represent the second ionization
energy of strontium - ans -Sr+ (g) --> Sr2+ (g) + e-
explain the differences in the melting points of phosphorus and chlorine - ans -
phosphorus has more electrons, so stronger London forces, so more energy is
required to break the intermolecular forces
describe the bonding in magnesium and silicon. include the names of the particles
and describe the forces between the particles in the structures - ans -magnesium
has metallic bonds, which contains cations and delocalised electrons. silicon has
covalent bonds between atoms
describe one difference between the sigma bond and the pi bond - ans -pi bonds
have sideways overlap, sigma bonds have head on overlap of orbitals
explain in terms of bond breaking and bond making, why the enthalpy change of
formation of NO is endothermic - ans -more energy is required for bond breaking
than is released by bond making
write 2 equations to show how NO radicals catalyse the breakdown of ozone - ans
-*NO + O3 --> *NO2 + O2
NO2 + O2 --> *NO + O2
, compare the electrical conductivities of solid and aqueous barium chloride - ans -
barium chloride does not conduct electricity when solid because it has ions that
are in a fixed position. barium chloride conducts when in aqueous solutions
because it has mobile ions
describe the use of aqueous barium chloride in qualitative analysis - ans -it is used
to test for sulfate, and a white precipitate forms
what is the electron configuration of a nitride ion? - ans -1s2 2s2 2p6
describe the oxidation reactions of butan-1-ol forming an aldehyde and a
carboxylic acid - ans -forming an aldehyde requires acid and dichromate, with
heating under distillation. the product formed is butanal. forming a carboxylic
acid requires acid and dichromate, with heating under reflux. the product formed
is butanoic acid. distillation apparatus contain a condenser with water flow, and a
collection of the organic product.
what are the reagents and conditions to form cyclohexene from
bromocyclohexene - ans -acid catalyst and heat
explain why group 2 elements are reducing agents - ans -group 2 metals add
electrons to other species
state and explain the trend in alkalinity of the solution formed when group 2
oxides are added to water - ans -group 2 oxides react with water forming the
metal hydroxide. hydroxide ions in solution cause alkalinity. down group 2, the
solubility of the metal hydroxide increases, increasing the pH and alkalinity
state and explain the trend in boiling points of the halogens fluorine to iodine -
ans -boiling point increases due to the increase in electrons down the group. this
increases the strength of the London forces and more energy is needed to break
the intermolecular forces
explain why it is important to carry out the carbonate test before carrying out the
sulfate test on an unknown chemical - ans -dilute nitric acid reacts with carbonate
ions ad no precipitate of barium carbonate will then form
