Unit 2: Organic 1 and Physical 1 Flashcards

The minimum kinetic energy colliding particles must possess for a collision to result in a chemical reaction.

The peak lowers and shifts to the right; the curve flattens; a much larger fraction of molecules have energy ≥ Ea; the total area remains constant.

A substance that increases reaction rate without being consumed; it provides an alternative reaction pathway with a lower activation energy (Ea).

Equilibrium shifts towards the side with fewer gas moles to oppose the increase in pressure.

Compounds with the same molecular formula but different structural formulas. Types: chain isomerism, position isomerism, and functional group isomerism.

Compounds with the same structural formula but different spatial arrangements of atoms in space.

1. Restricted rotation about the C=C double bond (due to the π-bond).
2. Each carbon of the double bond must be attached to two different atoms or groups.

Assign priority based on higher atomic number of the atom directly attached to the double-bond carbon. If priority groups are on the same side, it is the (Z) isomer; if on opposite sides, it is the (E) isomer.

Ultraviolet (UV) light (provides energy to homolytically break the halogen-halogen bond).

1. Initiation (creates radicals)
2. Propagation (maintains radical count while transforming reactants into products)
3. Termination (destroys radicals by combining two radicals into a stable molecule).

It is a toxic, colourless, odourless gas that binds with very high affinity to haemoglobin in red blood cells, displacing oxygen and preventing oxygen transport.

Thermal: High temperature and high pressure; produces high percentage of alkenes.
Catalytic: High temperature, slight pressure, zeolite catalyst; produces branched alkanes, cycloalkanes, and aromatics for motor fuels.

An electron-pair donor that possesses a lone pair of electrons or a negative charge.

Must start from a lone pair of electrons or from the centre of a covalent bond, and point directly to an atom or bond where a new bond/charge is formed.

Potassium cyanide (KCN) dissolved in aqueous ethanol under reflux (nucleophilic substitution; extends carbon chain by one carbon).

Excess concentrated ethanolic ammonia (NH₃) heated under pressure in a sealed tube (nucleophilic substitution; excess ammonia prevents multiple alkylation).

Hot ethanolic potassium hydroxide (KOH dissolved in ethanol) under reflux (hydroxide acts as a base/proton acceptor, producing an alkene).

An electron-pair acceptor (positively charged ion or partially positive end of a polar molecule).

Tertiary (3°) > Secondary (2°) > Primary (1°).
Alkyl groups release electron density via the positive inductive effect, spreading and stabilising the positive charge on the carbon atom.

When a hydrogen halide (HX) adds to an unsymmetrical alkene, the hydrogen atom adds to the double-bond carbon already bearing more hydrogen atoms, forming the more stable carbocation intermediate.

Aldehyde: Heated gently with acidified potassium dichromate(VI) and immediately distilled off as it forms.
Carboxylic acid: Heated under reflux with an excess of acidified potassium dichromate(VI).

Orange solution turns green (dichromate(VI) ions Cr₂O₇²⁻ are reduced to chromium(III) ions Cr³⁺).

There is no hydrogen atom attached to the carbon atom that carries the -OH group.

Tollens' reagent: Warm gently; produces a silver mirror on the glass wall.
Fehling's solution: Warm gently; blue solution forms a dark brick-red precipitate (Cu₂O).

Alcohol O-H: Broad absorption between 3230-3550 cm⁻¹.
Carboxylic acid O-H: Very broad absorption between 2500-3000 cm⁻¹ (overlaps C-H region).

The region below 1500 cm⁻¹. It contains a unique, complex pattern of peaks for every individual compound, used to verify identity by direct comparison with a database of known spectra.

Aldehyde: Gently heat with acidified potassium dichromate(VI) and immediately distil off the volatile aldehyde as it forms.
Carboxylic acid: Heat under reflux with an excess of acidified potassium dichromate(VI).

The orange solution turns green (orange dichromate(VI) ions Cr₂O₇²⁻ are reduced to green chromium(III) ions Cr³⁺).

There is no hydrogen atom bonded to the carbon atom that carries the -OH alcohol functional group.

Concentrated sulfuric acid (H₂SO₄) or concentrated phosphoric acid (H₃PO₄) catalyst with heating.

To act as a chemical drying agent, removing dissolved water droplets until the organic liquid turns completely clear.

Thermal: High temperature (700-1200 K) and high pressure (up to 7000 kPa); produces high percentage of alkenes.
Catalytic: High temperature (~720 K), slight pressure, zeolite catalyst; produces branched alkanes, cycloalkanes, and aromatics for motor fuels.

It is a toxic, colourless, odourless gas that binds with very high affinity to haemoglobin in red blood cells, displacing oxygen and preventing oxygen transport.

Ultraviolet (UV) light, which provides the photon energy required to homolytically break the halogen-halogen bond (photochemical initiation).

1. Initiation: creates radicals from stable molecules.
2. Propagation: radical reacts with molecule to produce a new radical and product.
3. Termination: two radicals combine to form a stable molecule.

1. CH₄ + Cl• → CH₃• + HCl
2. CH₃• + Cl₂ → CH₃Cl + Cl•

Homolytic fission, in which each bonding atom receives one electron from the shared covalent bond, forming two neutral free radicals.

1. Restricted rotation about the C=C double bond (due to the π-bond).
2. Each carbon atom of the C=C double bond must be attached to two different atoms or groups.

Assign priority to groups on each double-bond carbon by higher atomic number. If high-priority groups are on the same side, it is the (Z) isomer (zusammen); if on opposite sides, it is the (E) isomer (entgegen).

An electron-pair acceptor that attacks electron-rich regions (such as the π-bond of a C=C double bond).

Tertiary (3°) > Secondary (2°) > Primary (1°).
Alkyl groups release electron density via the positive inductive effect, dispersing and stabilising the positive charge on the carbon atom.

The hydrogen atom adds to the double-bond carbon atom that already carries more hydrogen atoms, because this forms the more stable (tertiary or secondary) carbocation intermediate.

Shake with bromine water. Orange bromine water is decolourised because bromine adds across the C=C bond.

Addition: Monomers with C=C double bonds join with no other products formed (100% atom economy).
Condensation: Monomers join with the elimination of a small molecule (such as H₂O or HCl). It can use two different difunctional monomers (e.g. dicarboxylic acid + diol/diamine) or a single bifunctional monomer (e.g. an amino acid or hydroxycarboxylic acid).

Pyramidal, 107°. The nitrogen atom has 3 bonding pairs and 1 lone pair.

Ethanol forms hydrogen bonds with water through its O-H group. Ethane cannot form hydrogen bonds with water.

Butan-1-ol molecules form hydrogen bonds with each other. Butanal has only permanent dipole-dipole and van der Waals forces, which are weaker.

pV = nRT
p in Pa, V in m³, n in mol, T in K (R = 8.31 J K⁻¹ mol⁻¹).

CH₂. C: 85.7 / 12.0 = 7.14. H: 14.3 / 1.0 = 14.3. Ratio C : H = 1 : 2.

It contains 4 electrons: a σ bond and a π bond.

When a system in dynamic equilibrium is subjected to a change in conditions, the position of equilibrium shifts to oppose that change.

No effect on either. A catalyst increases the rates of forward and reverse reactions equally, speeding up the approach to equilibrium without shifting its position.

The value of Kc decreases because equilibrium shifts in the reverse endothermic direction, decreasing product concentration and increasing reactant concentration.

The value of Kc increases because equilibrium shifts in the forward endothermic direction to absorb heat, increasing product concentration and decreasing reactant concentration.

No effect. The value of Kc is constant at a constant temperature; only temperature changes can alter Kc.

Towards the side with fewer gas moles to oppose the increase in pressure.

An electron-pair donor that possesses a lone pair of electrons (e.g. :OH⁻, :CN⁻, :NH₃) and attacks electron-deficient carbon atoms.

Warm aqueous sodium hydroxide (NaOH(aq)) or potassium hydroxide (KOH(aq)) under reflux (nucleophilic substitution).

Potassium cyanide (KCN) dissolved in aqueous ethanol heated under reflux (nucleophilic substitution; extends the carbon chain by one carbon).

Excess concentrated ethanolic ammonia (NH₃) heated under pressure in a sealed tube (nucleophilic substitution; excess NH₃ suppresses multiple alkylations).

Hot ethanolic potassium hydroxide (KOH in ethanol) heated under reflux; hydroxide acts as a base (proton acceptor) to form an alkene.

The minimum kinetic energy that colliding particles must possess for a collision to result in a chemical reaction.

The peak lowers and shifts to the right; the curve flattens; a significantly greater fraction of molecules have energy ≥ Ea; the total area remains constant.

Because a significantly greater fraction of molecules have kinetic energy greater than or equal to the activation energy (E ≥ Ea), leading to a higher frequency of successful collisions.

A catalyst provides an alternative reaction pathway with a lower activation energy (Ea), so a greater proportion of collisions are successful.

Because no molecules in a gas mixture have zero kinetic energy.

Tollens' reagent: Aldehyde forms a silver mirror; ketone gives no reaction.
Fehling's solution: Aldehyde turns blue solution to a brick-red precipitate (Cu₂O); ketone gives no reaction.

Add aqueous sodium carbonate (Na₂CO₃) or sodium hydrogencarbonate (NaHCO₃); effervescence / bubbles of carbon dioxide gas confirm carboxylic acid.

Alcohol O-H: Broad peak between 3230-3550 cm⁻¹.
Carboxylic acid O-H: Very broad peak between 2500-3000 cm⁻¹, overlapping the C-H stretching region.

A strong, sharp absorption peak between 1680-1750 cm⁻¹ (found in aldehydes, ketones, and carboxylic acids).

The region below 1500 cm⁻¹ contains a unique, complex pattern of peaks specific to a molecule. Comparing it against a computerised spectral library confirms exact molecular identity.

The simplest whole-number ratio of atoms of each element in a compound.

The actual number of atoms of each element in a molecule.

General: CₙH₂ₙ₊₁OH. Structural: CH₃CH₂CH₂CH₂OH. Empirical: C₄H₁₀O (the same as its molecular formula).

A family of compounds with the same functional group and general formula. Each member differs from the next by CH₂. They have similar chemical properties and a gradual trend in physical properties.

1-bromo-2-methylpropane. Substituents go in alphabetical order: bromo before methyl.

Homolytic: each atom gets one electron, giving two radicals. Heterolytic: one atom gets both electrons, giving two ions.

It starts at a lone pair or a covalent bond. It ends at an atom, or between two atoms where a new bond forms. It shows the movement of an electron pair.

Compounds with the same molecular formula but a different structural formula. Types: chain, position and functional group isomers.

A compound with the same structural formula but a different arrangement of the atoms in space.

Both start with C, so look at the next atoms. Ethyl has (C, H, H) and methyl has (H, H, H). Ethyl has the higher priority.

C₂H₄O: a three-membered ring of two carbon atoms and one oxygen atom (a cyclic ether). The ring bond angles are about 60°.

2CH₂=CH₂ + O₂ → 2C₂H₄O. Silver catalyst, about 250 to 300 °C, 1 to 2 MPa.

Complete combustion to CO₂ and H₂O must be avoided.

Ethene and oxygen mixtures can explode. The reaction is exothermic, with a runaway risk. Epoxyethane is toxic, carcinogenic, highly flammable and a gas at room temperature (boiling point 11 °C).

Ring strain: 60° angles instead of 109.5°, so the weak C-O bonds break easily. The polar C-O bonds make the ring carbons δ+, so nucleophiles attack them.

C₂H₄O + H₂O → HOCH₂CH₂OH (ethane-1,2-diol). Uses: antifreeze, and making polyester (PET).

C₂H₄O + CH₃OH → CH₃OCH₂CH₂OH (2-methoxyethanol), used as a solvent.

An alcohol with a long chain reacts with many epoxyethane molecules: ROH + n C₂H₄O → R(OCH₂CH₂)ₙOH. The long chain is hydrophobic and the (OCH₂CH₂)ₙOH end is hydrophilic.

The O lone pair of water attacks a δ+ ring carbon, and the ring C-O bond pair moves onto the ring O. This gives an intermediate with O⁻ and O⁺H₂. A proton transfers from O⁺ to O⁻, giving the diol.

100%, because all the atoms end up in the product.

KCN in ethanol and water, reflux. Product: propanenitrile, CH₃CH₂CN. The chain gains one carbon.

Step 1: the NH₃ lone pair attacks the δ+ carbon and Br⁻ leaves, giving CH₃CH₂NH₃⁺. Step 2: a second NH₃ removes H⁺, giving CH₃CH₂NH₂ + NH₄⁺.

To limit further substitution. The amine product also has a lone pair and could react again.

In water, warm: OH⁻ is a nucleophile, giving propan-2-ol. In ethanol, hot: OH⁻ is a base, giving propene. Both reactions happen at the same time.

The OH⁻ lone pair attacks an H on a carbon next to the C-Br carbon. The C-H bond pair forms the C=C. The C-Br bond pair moves onto Br, and Br⁻ leaves.

The C=C electrons repel the electrons in the Br-Br bond. This induces a dipole, Brδ+ to Brδ−, and the C=C attacks the Brδ+.

An alkyl hydrogensulfate, for example CH₃CH₂OSO₃H. Warming it with water hydrolyses it to the alcohol.

Write poly, then the monomer name in brackets, for example poly(propene) and poly(chloroethene).

The chains are saturated, with strong non-polar C-C and C-H bonds.

Its small molecules get between the chains and push them apart. This weakens the forces between the chains, so they can slide.

The change in concentration of a reactant or product per unit time. Usual units: mol dm⁻³ s⁻¹.

Most colliding particles have energy less than the activation energy, or they are not correctly oriented.

More particles in the same volume, so collisions are more frequent. So there are more collisions with E ≥ Ea per unit time.

One curve (the temperature is the same) with two Ea lines. Ea with a catalyst is lower, to the left, so more particles have E ≥ Ea.

It shifts to the right, to remove the added reactant. Kc does not change.

A low temperature gives a higher yield (the forward reaction is exothermic) but a slow rate. 450 °C is a compromise.

A high pressure gives a higher yield (4 mol of gas form 2 mol) and a faster rate, but it is expensive and needs strong equipment.

Nitrogen oxides (NOx), carbon monoxide (CO), carbon (soot) and unburned hydrocarbons.

2CO + 2NO → 2CO₂ + N₂. Platinum and rhodium (Pt/Rh) on a ceramic honeycomb.

SO₂ is acidic, so a base removes it. CaO + SO₂ → CaSO₃. CaCO₃ + SO₂ → CaSO₃ + CO₂. The product can be oxidised to calcium sulfate (gypsum).

Distil with excess alcohol: the aldehyde is removed as it forms. Reflux with excess oxidising agent: the carboxylic acid forms.

1. A lone pair on the O of -OH takes H⁺. 2. Water leaves, giving a carbocation. 3. H⁺ is lost from the next carbon, forming C=C.

Alcohols made by fermentation are dehydrated to alkenes. The alkenes are used to make addition polymers, so no monomers from crude oil are needed.

It measures m/z to 4 decimal places. Compare with precise Mr values: 58.0417 is C₃H₆O, not C₄H₁₀ (58.0780) or C₂H₂O₂ (58.0054).

An O-H bond. An aldehyde has no O-H, so the sample contains unreacted alcohol as an impurity.

Their bonds absorb infrared radiation emitted by the surface of the Earth. The energy is re-emitted in all directions, some back towards the Earth, which warms the atmosphere.