How to tell if a molecule is polar or non-polar without electronegativity

Provide a stepwise curved arrow mechanism that fully explains the outcome of the reaction shown below. oh нао* heat он

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

Given the following at 25c calculate delta hf for hcn (g) at 25c. 2nh3 (g) +3o2 (g) + 2ch4 (g) > 2hcn (g) + 6h2o (g) delta h rxn= -870.8 kj. delta hf=-80.3 kj/mol for nh3 (g), -74.6 kj/mol for ch4, and -241.8 kj/mol for h2o (g)