2025 · Paper 2 · Chemistry
Question 16
The printed question, the official key, and each model’s JSON answer plus the reasoning it wrote.
Q16
Official 2
Model answers
Claude Fable 5.1
Anthropic
2
Claude Fable 5.1 reasoning
Let the octasaccharide contain x ribose, y 2-deoxyribose, z glucose units with x + y + z = 8. Complete hydrolysis of a linear octasaccharide consumes 7 H₂O, so total mass of monosaccharides = 1024 + 7×18 = 1150 g per mole. 150x + 134y + 180z = 1150 Mass of 2-deoxyribose = 0.5826 × 1150 ≈ 670 g → y = 670/134 = 5. Then x + z = 3 and 150x + 180z = 1150 − 670 = 480. 150x + 180(3 − x) = 480 → 540 − 30x = 480 → x = 2, z = 1. Check: 2(150) + 5(134) + 1(180) = 300 + 670 + 180 = 1150 ✓; 670/1150 = 58.26% ✓. Number of ribose units = 2.
GPT 6 Astra
OpenAI
2
GPT 6 Astra reasoning
No written reasoning was returned for this item.
GPT 5.6 Luna
OpenAI
2
GPT 5.6 Luna reasoning
No written reasoning was returned for this item.