75-Archetype SyllabusChemistry • ARCH-C-12 • Spec C13

Full 6-Card Lesson 15-Question Timed Drill

UAT-UK SPEC CODE: C13 (Carbon / Organic chemistry)ASSUMED MATHS 1 PREREQUISITE: M3.5FREQUENCY: MEDIUM

C1–C6 Organic Functional Groups, Structural Isomers, Alcohol Oxidation, Esterification & Polymers

Deconstructed from 10 past UAT-UK questions (4.44% of all historical Chemistry papers). Students using standard A-Level classroom methods spend an average of 135s on this archetype—blowing past the 90s ESAT budget. Using the 2-line Sub-90 heuristic below compresses solve time to 35s (saving 100s per question).

Historical Frequency

10 Past Qs

4.44% of Chemistry

Classroom Trap Time

135s

+45s over 90s budget

Sub-90 Target Time

35s

Banks +100s on the clock

Dominant UI Format

5-Option A–E

Maths 1 Skill: M3.5

Card 1 & Card 2 Preview: The Classroom Time Trap vs. Sub-90 2-Line Rule

Excerpted from our interactive 6-Step Topic Lesson for ARCH-C-12.

Launch All 6 Active-Recall Cards

CARD 1 OF 6 • THE CLASSROOM TIME TRAP (135s)

Why Students Bleed Time:

Systematically shorten the longest carbon chain for

\text{C}_5\text{H}_{12}

: (1) **

5

-carbon chain:** pentane,

\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{CH}_3

. (2) **

4

-carbon chain:** methylbutane,

\text{CH}_3\text{CH(CH}_3)\text{CH}_2\text{CH}_3

(note that placing the methyl on

\text{C2}

\text{C3}

gives the exact same molecule). (3) **

3

-carbon chain:** dimethylpropane,

\text{C(CH}_3)_4

. Total

= 3

structural isomers (~95s).

In 10 past UAT-UK questions (4.44% of Chemistry), candidates lose 100s by every addition monomer must first be drawn as c=c with 4 attached groups; the repeat unit has a single c-c bond of length 2 carbons inside the brackets. Instead, apply C13 with Maths 1 skill M3.5.

CARD 2 OF 6 • THE 2-LINE SUB-90 HEURISTIC (<35s)

Line 1 (Chain-Length Reduction):

\text{C}_5

chain (

1

: pentane)

+ \text{C}_4

chain (

1

: methylbutane)

+ \text{C}_3

chain (

1

: dimethylpropane).

Line 2 (Sum):

1 + 1 + 1 = 3

(20s).

Sanity & Limit Check: Verify units/signs against fence_post_or_domain_trap (Drawing an addition polymer repeat unit with a C=C double bond still inside the bracket, or putting more than 2 backbone carbon atoms in the main chain) and factor_of_two_or_stoichiometry_trap (Using general formula C_nH_{2n+2} instead of C_nH_{2n} for cycloalkanes or monounsaturated alkenes, or forgetting the -18 (H2O lost) per ester/amide link in condensation polymers).

Examiner Distractor Blueprint for ARCH-C-12

FOIL #1fence_post_or_domain_trap

Drawing an addition polymer repeat unit with a C=C double bond still inside the bracket, or putting more than 2 backbone carbon atoms in the main chain

Every addition monomer must first be drawn as C=C with 4 attached groups; the repeat unit has a single C-C bond of length 2 carbons inside the brackets.

Open Fence-Post / Domain Trap Clinic

FOIL #2factor_of_two_or_stoichiometry_trap

Using general formula C_nH_{2n+2} instead of C_nH_{2n} for cycloalkanes or monounsaturated alkenes, or forgetting the -18 (H2O lost) per ester/amide link in condensation polymers

Each ring or double bond removes 2 H atoms; each condensation linkage eliminates 1 molecule of H2O (M_r = 18).

Open Factor-of-2 / Stoichiometry Clinic

FOIL #3sign_or_direction_flip

Swapping the alcohol-derived alkyl prefix (e.g. propyl) and carboxylic acid-derived alkanoate suffix (e.g. ethanoate) when naming or hydrolysing an ester

In R'-COO-R, the -O-R group comes from the alcohol (alkyl prefix) and the R'-C=O group comes from the carboxylic acid (-oate suffix).

Open Sign / Direction Flip Clinic

FOIL #4fence_post_or_domain_trap

Double-counting mirrored chain structures (e.g. 2-methylbutane drawn from both ends) as distinct structural isomers

Failing to apply IUPAC lowest-locant numbering to verify whether two drawn structures are identical.

Open Fence-Post / Domain Trap Clinic

Try 1 Live Sample Question Under the 90-Second Stopwatch

Press W to open the 2-line dry-wipe scratchpad, select A–E, and lock in to reveal the Dual-View solution.

Full 6-Card Lesson Launch All 15 Questions (ARCH-C-12)

ARCH-C-12: C1–C6 Organic Functional Groups, Structural Isomers, Alcohol Oxidation, Esterification & Polymers (Sample)Chemistry

00:00.0

SUB-90 ZONE (<35S)

0.0s35s Sub-9090s ESAT Budget150s Classroom

Question 1 of 1ARCH-C-12 (6-Card Lesson)Format: Standard 5-Option

Right-click any option to cross out • Keys A–E + Enter

Question 1 of 1 • 90s Target

Ready to Start Question 1?

The question stem, diagram, and answer options are hidden behind this pre-start gate. When you click below, the question will reveal and your 90-second split stopwatch will immediately begin ticking.

Chemistry•ARCH-C-12•Standard 5-Option

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