What is the electron configuration of calcium, which has 20 electrons?

Light waves can move through , but they travel fastest when they move through a(n) .

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?

Which change to the system wood cause the freely-moving piston to lower?