Domain: Natural Science — Chemistry
Target concept: Amide formation via ammonolysis of esters results in a precipitate.

Video generation prompt: Add 1 mL of 0.1 M diethyl oxalate solution to 2 mL of concentrated ammonia solution and allow to stand at room temperature for 5 minutes.

Evaluation guide:
(i) Target concept: Nucleophilic acyl substitution where ammonia acts as nucleophile on diethyl oxalate (a diester with two adjacent carbonyl groups), yielding ethanol and oxamide; oxamide is only sparingly soluble in water and precipitates readily as a fine white solid, even without heating.
Minimum mechanism: Diethyl oxalate must be present as the diester reactant; ammonia must be present in excess as a concentrated aqueous solution; the two adjacent carbonyl groups make the oxalate ester markedly more reactive toward ammonia than an ordinary monoester, so the reaction proceeds visibly at room temperature without added catalyst or heat; the precipitate must be oxamide -- solid, white, finely granular, and only sparingly soluble -- with no competing hydrolysis or decomposition products.
(ii)Storyline: [Phase 1: Setup] Two labeled vials (diethyl oxalate, concentrated ammonia) shown side-by-side in fixed frame. [Phase 2: Action] Diethyl oxalate solution is transferred as a coherent liquid stream into the ammonia vial. [Phase 3: Mixing & Stillness] Brief gentle swirl -> immediate cessation of motion -> uninterrupted view of combined solution. [Phase 4: Emergence] White granular precipitate appears *only after* transfer completes and *during* stillness, increasing in density over time. [Perspective constraint] Fixed frontal viewpoint; no occlusion; all events occur within same field of view; precipitate must be clearly visible to the eye, not merely a faint haze.

Manual:
Experimental Procedure
1. Place labeled vial of 0.1 M diethyl oxalate solution and labeled vial of concentrated ammonia solution side-by-side.
2. Transfer 1 mL diethyl oxalate solution into 2 mL concentrated ammonia solution using dropper or pipette.
3. Gently swirl once, then let mixture stand undisturbed for 5 minutes.
Observation of Experimental Phenomena
A white, finely divided precipitate forms in the mixture shortly after addition and remains suspended/settling during standing.
Summary of Experimental Principles
Ammonolysis of the diester (diethyl oxalate) produces oxamide, a solid diamide that is only sparingly soluble in water, giving a visible precipitate even without heating; the two adjacent carbonyl groups of the oxalate ester make it far more reactive toward ammonia than a simple monoester such as ethyl acetate.

Prompt Grounding rubric:
level_1: No diethyl oxalate solution container and no ammonia solution container are visible; no liquid transfer between them is shown; no standing/waiting period is depicted; none of the three core elements (diethyl oxalate solution, ammonia solution, and a shared mixing container) appear.
level_2: At least one correct container is visible, but the wrong number of solutions is shown (e.g. only one solution present); the transfer action is missing or shows the wrong liquid being added (e.g. plain water instead of diethyl oxalate); or there is no depiction of a stillness period after mixing.
level_3: Both the diethyl oxalate solution container and the ammonia solution container are visible; the diethyl oxalate solution is transferred into the ammonia container; the mixing container holds both liquids together; and a post-transfer stillness period is shown, with no further action for at least a second or two while both liquids sit together.
level_4: Everything required at the 3-point level holds, and in addition the relative fill amounts look consistent with a smaller volume of diethyl oxalate solution added to a roughly double volume of ammonia solution, the containers keep their distinct identity (no labels merging or disappearing), and the stillness period is shown as one uninterrupted view of the mixture.
level_5: Everything required at the 4-point level holds, and in addition the diethyl oxalate container looks visibly smaller (or is labeled to match) than the ammonia container, the transfer happens in one continuous motion without pausing or reversing partway, and the stillness period is shown as an uninterrupted, fixed view of the mixture for at least three seconds with no camera movement or blocked view.

Scientific and Causal Correctness rubric:
level_1: No precipitate ever appears; the mixture stays fully clear and uniform the whole time; there is no visible change of state at all; the color never changes from start to finish; and nothing visually ties the addition of diethyl oxalate to any observable result.
level_2: A precipitate appears, but it doesn't match amide formation (e.g. gas bubbles, an unexpected color change, haze without any granular solid, or a solid that dissolves again right away); or the precipitate appears before the transfer is finished or during the transfer itself, with no visible link between the completed addition and the precipitate's onset.
level_3: A white precipitate, consistent with the expected oxamide product, appears after the transfer is complete and during the stillness period; it looks granular or particulate rather than filmy or oily; it stays suspended or settles slowly rather than dissolving instantly or floating off; and it only shows up once the two liquids have fully combined and nothing further is happening.
level_4: Everything required at the 3-point level holds, and in addition the precipitate appears only in the shared mixing container (not in either source container), it does not appear during the transfer itself, it stays within the liquid volume rather than clinging only to the walls or surface, and no separate color shift, bubbling, or splitting into two clear layers happens alongside it.
level_5: Everything required at the 4-point level holds, and in addition the oxamide precipitate stays continuously visible from when it first appears until the end of the clip, it keeps its grainy, particulate look rather than clumping into a film or gel, it never briefly clears up or redissolves, and it appears spread through the lower portion of the liquid rather than being confined to just the very bottom edge or the surface.

Spatiotemporal Consistency rubric:
level_1: Objects abruptly change position or orientation between frames with no connecting motion; the container appears or disappears mid-pour; liquid appears or vanishes partway through pouring; the lighting shifts abruptly between shots; the background disappears or changes; or multiple incompatible camera angles are shown in the same continuous scene.
level_2: The pouring motion contains visible jumps or missing frames; the precipitate appears instantly with no gradual build-up; the container rotates or tilts with no visible cause; the lighting flickers or shadows fall inconsistently; or background elements warp or distort across frames.
level_3: Only minor, brief inconsistencies appear (e.g. a very short freeze during the stillness period, or a slight shadow shift); any camera movement is a subtle drift rather than a jump, with no object actually changing position; the source containers, if both shown, stay in the same relative arrangement, and the mixing container stays centered in frame.
level_4: Everything required at the 3-point level holds, and in addition the pouring motion looks smooth with no sudden speed changes, the lighting and shadows stay consistent for the whole clip, the container rim keeps a rigid, undistorted shape, and the overall layout (source containers side by side, mixing container in the same spot) stays fixed throughout.
level_5: Everything required at the 4-point level holds, and in addition there is no visible shake or jitter in the shot, the brightness and color balance stay even from start to finish, the foreground and background do not shift relative to each other, the container's outline stays clear and stable in every frame, and the clip reads as one continuous take with no visible cuts, fades, or dissolves.