Number of atoms of phosphorus vapour in 100 gm

Which real-world scenarios below represent physical and chemical changes? -running a car -exploding fireworks -mixing water and powdered drink mix -combining oil and vinegar to make salad dressing -taking aspirin for a headache -diluting bleach with water-digesting dinner-spreading peanut butter on bread

Which compound contain an iron with a 3+ charge

Explain in detail of the four major scientific developments that spurred the formulation of the plate tectonics theory