Lesson-specific diagram for Stoichiometric investigation: gas collection and uncertainty. It visualizes the reasoning sequence tied to $\text{measured amount}\to\text{stoichiometric prediction}\to\text{uncertainty}$. Text alternative: A gas-generation investigation connects a balanced reaction to measured volume while requiring explicit safety, collection assumptions, and uncertainty. Choose a representation that matches the chemical scale and evidence; do not infer more precision or mechanism than the data support.