Maybelline Cousteau’s backup oxygen tank reads 650 torr while on her boat, where the temperature is 27 degrees C. When she dives down to the bottom of an unexplored methane lake on a recently-discovered moon of Neptune, the temperature will drop down to –183 degrees C. What will the pressure in her backup tank be at that temperature?

180torr

Explanation:

Using P1VI/T1= P2V2/T2

where

p1= 650 torr

p2=??

T1= 27°C =  27°C + 273= 300K

T2= -183°C= -183°C +273=90K

V1= V2 ie volume is constant

SOLUTION

 1 torr= 1mmHg

P1VI/T1= P2V2/T2, where V1=V2

= P1/TI= P2/T2

600/300=P2/90

P2= 600X90/300= 180 torr

  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-