# Answer to Question #42233 in Molecular Physics | Thermodynamics for David

Question #42233

PuO2 has a density of 11.5 gcm-3 and a specific heat capacity of 330 J kg-1 K-1

. A fresh sample (i.e. one that has not decayed) of PuO2 produces 0.540 kW kg-1 of heat due to internal radioactive decay*. For this question we will consider a 1 cm^3 block of PuO2.

a) How much heat does a fresh 1 cm^3 block of PuO2 produce?

A fresh 1 cm^3 block sitting on the bench in the lab glows red hot at 700 K as it looses heat to

its environment.

b) If we place the block, initially at 700K, in a very well insulated container, its temperature will

start to rise. How long does it take for the block to reach 1000 K?

c) PuO2 melts at 2673 K and its latent heat of fusion is 245 kJ kg-1. If we place our block in a well insulated and heat resistant container when it is at 700 K, then how long is it before the whole block is melted?

. A fresh sample (i.e. one that has not decayed) of PuO2 produces 0.540 kW kg-1 of heat due to internal radioactive decay*. For this question we will consider a 1 cm^3 block of PuO2.

a) How much heat does a fresh 1 cm^3 block of PuO2 produce?

A fresh 1 cm^3 block sitting on the bench in the lab glows red hot at 700 K as it looses heat to

its environment.

b) If we place the block, initially at 700K, in a very well insulated container, its temperature will

start to rise. How long does it take for the block to reach 1000 K?

c) PuO2 melts at 2673 K and its latent heat of fusion is 245 kJ kg-1. If we place our block in a well insulated and heat resistant container when it is at 700 K, then how long is it before the whole block is melted?

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