In the balanced equation Cu + 2 HCl --> CuCl2 + H2, if you start with 0.15mol Cu and 0.38mol HCl, how many moles of HCl are left over (which means unused)?

If one fission reaction of a uranium-235 atom produced two neutrons, how many neutrons would be released if the chain reaction occurred three more times?

If it is an isoelectronic series select true, if not select false. o2-, s2-, se2-, te2- na+, k+, rb+, cs+ n3-, p3-, as3-, sb3- ag, cd+, sn3+, sb4+ f-, cl-, br-, i- f-, ne, na+, mg2+ s2-, s, s6+

What is the empirical formula of a compound that is 50.7% antimony and 49.3% selenium ?