How much heat is required to change 48.5 liquid mercury (Hg) at 400 K to vapor at a 700 K? The boiling point of mercury is 629.88 K


-88 kj

-204 kj

16.2 kj

30 kj

29 kj

Respuesta :

Answer: 4.91 kJ

Explanation:

The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.

[tex]Q=m\times c_l\times (T_(f,l)-T_(i,l))+m\imes L+m\times c_v\times T_(f,v)-T_(i,v)[/tex]

Q = Heat absorbed = ?

m= mass of mercury = 48.5 g  = 0.0485 kg

c = specific heat capacity = [tex]0.14kJ/kgK[/tex]

L = heat of vaporization = 59.2 kJ

Initial temperature of liquid mercury = [tex]T_i[/tex] = 400 K

Final temperature of mercury vapor = [tex]T_f[/tex]  = 700 K

Putting in the values, we get:

[tex]Q=0.0485\times 0.14\times (629.88-400)+0.0485\times 59.2+0.0485\times 0.14\times (700-629.88)[/tex]

[tex]Q=1.56+2.87+0.476[/tex]

[tex]Q=4.91kJ[/tex]

Answer:

16.2 kj

Explanation:

1.56kj + 14.31kj + 0.34kj