Phosphine, PH3(g) , decomposes according to the equation4PH3(g)⟶P4(g)+6H2(g)The kinetics of the decomposition of phosphine at 950 K was followed by measuring the total pressure in the system as a function of time. The data in the table were obtained in a run where the reaction chamber contained only pure phosphine at the start of the reaction. Time (min)Ptotal (Torr)0.0010040.015180.0168100171

a chemical reaction

explanation:

the answer for sodium is 0.186

the answer for rubidium is 0.251

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.