Question

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

Answer 1

16.2 kj

Step-by-step explanation:

1.56kj + 14.31kj + 0.34kj

Answer 2

Answer: 4.91 kJ

Step-by-step explanation:

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

`Q=m* c_l* (T_(f,l)-T_(i,l))+m\imes L+m* c_v* T_(f,v)-T_(i,v)`

Q = Heat absorbed = ?

m= mass of mercury = 48.5 g = 0.0485 kg

c = specific heat capacity =
`0.14kJ/kgK`

L = heat of vaporization = 59.2 kJ

Initial temperature of liquid mercury =
`T_i` = 400 K

Final temperature of mercury vapor =
`T_f` = 700 K

Putting in the values, we get:

`Q=0.0485* 0.14* (629.88-400)+0.0485* 59.2+0.0485* 0.14* (700-629.88)`

`Q=1.56+2.87+0.476`

`Q=4.91kJ`