What is the entropy change of 0.6kg of steam at 1atm pressure and 100oC, when it condenses to 0.6kg of water at 100oC?
PLS HELP ME!!!
To find the entropy change during the condensation process, we can use the equation:
ΔS = m (saturated vapor entropy - saturated liquid entropy)
First, we need to find the saturated vapor entropy of steam at 1 atm and 100°C. Let's call this value S_vapor.
To find S_vapor, we can use steam tables or lookup charts. From the tables, we find that at 1 atm and 100°C, the saturated vapor entropy of steam is approximately:
S_vapor = 7.79 kJ/(kg·K)
Next, we need to find the saturated liquid entropy of water at 100°C. Let's call this value S_liquid.
Again, referencing the steam tables, we find that at 100°C, the saturated liquid entropy of water is approximately:
S_liquid = 1.21 kJ/(kg·K)
Now, we can calculate the entropy change:
ΔS = 0.6 kg * (S_vapor - S_liquid)
= 0.6 kg * (7.79 kJ/(kg·K) - 1.21 kJ/(kg·K))
≈ 3.948 kJ/K
Therefore, the entropy change of 0.6 kg of steam condensing to 0.6 kg of water at 100°C is approximately 3.948 kJ/K
To calculate the entropy change during a phase change, such as the condensation of steam to water, we need to use the formula:
ΔS = m × L / T
where:
ΔS is the entropy change
m is the mass of the substance
L is the latent heat of the substance
T is the temperature at which the phase change occurs
In this case, we have steam condensing into water, so we need to find the latent heat of vaporization for water at 100°C.
The latent heat of vaporization of water at 100°C is approximately 2260 kJ/kg.
Now we can plug the values into the formula:
ΔS = 0.6 kg × 2260 kJ/kg / (100 + 273.15) K
First, let's convert the °C temperature to Kelvin by adding 273.15 to 100°C.
ΔS = 0.6 kg × 2260 kJ/kg / (100 + 273.15) K
Now, let's calculate the value:
ΔS ≈ 5.46 kJ/K
Therefore, the entropy change of 0.6 kg of steam condensing to 0.6 kg of water at 100°C is approximately 5.46 kJ/K.
ΔS = ΔQ/T. ΔQ = -mL, m = mass of water, L= latent heat of vaporization = xxxxxx J/kg.
ΔS = -(0.6 kg)(xxxxx J /kg)/273 K = xxxxx J/K.
No change of temparature. Put in the values.