Heat transfer from cooling lava

[suchjoe]

Homework Statement

The world's most active volcanos, such as the Kilauea volcano in Hawaii, can disgorge about 5 ✕ 105 m3 of 1000°C lava per day. What is the rate of heat transfer out of the Earth by convection if this lava has a density of 2800 kg/m3 and eventually cools to 32°C? Assume that the specific heat of lava is the same as that of granite. Answer in MW.

Homework Equations

D=m/v
Q=mc(tf-ti)
P = Q/t

The Attempt at a Solution

Solved the density equation for mass (m=1.4*10E9kg)
Solved for Q (Q=1.07*10E15J)
Solved for P (P=1.24*10E10W or 12400MW)

Followed an example from book, what am I missing

 

[haruspex]

I take it your answer has been marked wrong. I get 12390MW, so I would probably have been marked wrong too.

 

[suchjoe]

Thanks for trying

 

[Chestermiller]

What about the heat of solidification?

 

[suchjoe]

Thanks chestermiller been searching for fusion number for granite found 100cal/gm can anyone verify