2025 · Paper 2 · Chemistry
Question 9
The printed question, the official key, and each model’s JSON answer plus the reasoning it wrote.
ChemistryPaper 2Numerical
Q09
Official 10.85 – 11.1
Model answers
Claude Fable 5.1
Anthropic
Correct4 / 4
11
Claude Fable 5.1 reasoning
Density = Z·M / (N_A · a³) For ccp (fcc), Z = 4. a = 400 pm = 4 × 10⁻⁸ cm, so a³ = 64 × 10⁻²⁴ cm³ = 6.4 × 10⁻²³ cm³. ρ = (4 × 105.6) / (6 × 10²³ × 6.4 × 10⁻²³) = 422.4 / 38.4 = 11.00 g cm⁻³
GPT 6 Astra
OpenAI
Correct4 / 4
11
GPT 6 Astra reasoning
No written reasoning was returned for this item.
GPT 5.6 Luna
OpenAI
Wrong0 / 4
110
GPT 5.6 Luna reasoning
No written reasoning was returned for this item.