Which is an example of physical weathering? limestone in rock dissolving when acid rain flows across it

bits of rock rusting when exposed to oxygen and water

wind blowing off bits of a rock over time

oxidation of certain metals in rock

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?