Question

A 5.0 g ice cube at -20°C is in a rigid, sealed container from which all the air has been evacuated. How much heat is required to change this ice cube into steam at 200°C? Steam has CV = 1500 J/kgK and CP = 1960 J/kgK

Short answer

15.9 kJ heat is required to change this ice cube into steam at 200°C

Step-by-step solution

Description of provided information 

A 5.0 g ice cube at -20°C is in a rigid, sealed container from which all the air has been evacuated.

The required heat for the heating process:

$Q=cm∆T$

Result of finding the accurate heat

The required heat for the heating process:

$Q=cm∆T$

For the phase transition

Q=mL

For melting $L_f=3.03·{10}^5$

For evaporating $L_v=22.6·{10}^{5}J/kg$

Thus the needed heat is on the basis of numeric values:

$Q=0.005·(2090·20+3.03·{10}^5+41.90·100+22.6·{10}^5+1500·100)=15869J$

As 5g =0.005 kg, the accurate answer is 15.9 kJ.