A flask contains a mixture of hydrogen gas and water vapor at STP. If the pressure of the water vapor is 19.5 mmHg, then what is the pressure of the hydrogen gas? 779 mmHg
779 mmHg

760 mmHg
760 mmHg

81.7 mmHg
81.7 mmHg

741 mmHg

the answer is b & c i believe : )

  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-

confused

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