What is the half‑life of an isotope that decays to 25% of its original activity in 85.6 h

Achange in the number of neutrons in an atom will change an blank . when the number of protons changes in an atom, a new element will form.

Match the mixture with the substance// i really need on this guys (it’s a pic btw)

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?