How many photons are produced in a laser pulse of 0.332 J at 597 nm

According to each substances heat of fusion, which of the items below requires more heat to be added per gram of substance to go from solid to liquid? silver sulfur water lead

Which terms are used to identify pure substances

Hydrogenation reactions, in which h2 and an "unsaturated" organic compound combine, are used in the food, fuel, and polymer industries. in the simplest case, ethene (c2h4) and h2 form ethane (c2h6). if 140 kj is given off per mole of c2h4 reacting, how much heat (in mj) is released when 12 kg of c2h6 forms?