How many moles of gas are in 12 liters of O2

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?

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+

Weight is a measure of: inertia force matter mass