# the specific heat of mercury is .03 cal/g*C,and its boiling point is 357*C.the specfic heat of water is 1 cal/g*C .it takes 65 calories of energy to vaporize one gram of mercury and 540 calories to...

the specific heat of mercury is .03 cal/g*C,and its boiling point is 357*C.the specfic heat of water is 1 cal/g*C .it takes 65 calories of energy to vaporize one gram of mercury and 540 calories to vaporize 1 gram of water .if both substances begin at room temperature (about 22*C),does it takes more energy to boil a gram of mercury or a gram of water ?show your calculations

(B) Mercury calculations (B)Water calculations

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### 1 Answer

Heat is required for two purposes:

1) To raise the temperature of the liquid at `22^o C` till its boiling point.

2) To convert the liquid at its boiling point into vapour.

For mercury:

`H_1=m*s*(t_2-t_1)`

`=1*0.03*(357-22)`

`=1*0.03*335`

`=10.05` cal

`H_2` =latent heat*mass

`=65*1=65` cal

Hence,` H=H_1+H_2`

`=(10.05+65)=75.05` cal

For water:

`H_1=m*s*(t_2-t_1)`

`=1*1*(100-22)`

`=78` cal

`H_2` =latent heat*mass

=`540*1=540` cal

Hence, `H=H_1+H_2`

=`(78+540)=618` cal

Therefore, it takes more energy to boil a gram of water than to boil a gram of mercury.