Calculate the heat in kilojoules needed to condense 185g of steam at 100 ∘C.
To do this, you need the the latent heat of vaporization (Lv) for water.
In references, the Lv for water is 2256 J/g.
The formula for the heat released of absorbed is
Q = m * Lv
where
m = mass
Lv = heat of vaporization
In this case, heat is released (negative Q) because the steam is condensed.
Substituting,
Q = 185 * 2256
Q = ?
Now solve for Q. Units are in J so divide it by 1000 to convert it to kJ.
Hope this helps :3
To calculate the heat needed to condense steam, we need to consider two steps: raising the temperature of the steam to its boiling point and then condensing the steam into water at the same temperature.
Step 1: Calculating the heat required to raise the temperature of the steam from 100°C to its boiling point.
The specific heat capacity of steam is approximately 2.03 J/g°C. We can use this value to calculate the heat required to raise the temperature using the formula:
q1 = mass × specific heat capacity × ΔT
Where:
q1 = heat required to raise the temperature
mass = mass of the steam (185g)
specific heat capacity = specific heat capacity of steam (2.03 J/g°C)
ΔT = temperature change (boiling point - initial temperature)
ΔT = 100°C - 100°C = 0°C
q1 = 185g × 2.03 J/g°C × 0°C = 0 J
Step 2: Calculating the heat required to condense the steam.
The heat of vaporization of water is approximately 40.7 kJ/mol. To calculate the heat required to condense the steam, we need to convert the mass of steam (185g) to moles using the molar mass of water.
The molar mass of water (H₂O) is approximately 18.02 g/mol.
moles = mass / molar mass
moles = 185g / 18.02 g/mol ≈ 10.274 mol
Now, we can calculate the heat required to condense the steam using the formula:
q2 = moles × heat of vaporization
q2 = 10.274 mol × 40.7 kJ/mol = 418.62 kJ
Therefore, the heat required to condense 185g of steam at 100°C is approximately 418.62 kilojoules.