Heat required to melt an iceberg

[ttk3]

Homework Statement

I think I'm doing this problem correctly... I'm not sure about my change in temperature value. Any suggestions?



Icebergs in the North Atlantic present hazards to shipping, causing the length of shipping routes to increase by about 30 percent during the iceberg season. Attempts to destroy icebergs include planting explosives, bombing, torpedoing, shelling, ramming, and painting with lampblack. Suppose that direct melting of the iceberg, by placing heat sources in the ice, is tried. How much heat is required to melt 12 percent of a 1.30×105 metric-ton iceberg? One metric ton is equal to 103 kg. Assume that the iceberg is at 0°C. (Note: To appreciate the magnitude of this energy, compare your answer to the Hiroshima atomic bomb which had an energy equivalent to about 15,000 tons of TNT, representing an energy of about 6.0×1013 J.)

Homework Equations

Q = c*m*change in temperature

The Attempt at a Solution

Miceberg = 1.30E8 kg
12% of iceberg = 1.56E7 kg
C ice = 2.00E3

Q = 2.00E3 * 1.30E8 * 1

Q = 3.12 E 5 J

 

[Astronuc]

Q = c*m*change in temperature

Is not correct if one is melting ice to liquid at °C. One needs the specific heat of fusion. This is only a phase change, which does not involve a temperature change.

See - http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/phase.html#c1

 

[ttk3]

Ah... thank you

 

[Ojizo88]

Youre using the wrong equation. Like has been stated, its a phase change and the formula would be $$Q = m L_{f}$$ where $$L_{f}$$ is the latent heat of fusion for water. IIRC its around 80 kcal/kg for water.