1 answer · Chemistry
Best Answer
Water steam condenses if its pressure is equal to vapor saturation vapor pressure.
Use the Clausius-Clapeyron relation.
I states the temperature gradient of the saturation pressure is equal to the quotient of molar enthalpy of phase change divided by molar volume change due to phase transition time temperature:
dp/dT = ΔH / (T·ΔV)
Because liquid volume is small compared to vapor volume
ΔV in vaporization is approximately equal to to the vapor volume. Further assume ideal gas phase:
ΔV ≈ V_v = R·T/p
Hence
dp/dT = ΔHv / (R·T²/p)
<=>
dlnp/dT = ΔHv / (R·T²)
If you solve this DE an apply boundary condition p(T₀)= p₀.
you get the common form:
ln(p/p₀) = (ΔHv/R)·(1/T₀ - 1/T)
<=>
p = p₀·exp{(ΔHv/R)·(1/T₀ - 1/T)}
For this problem use normal boiling point of water as reference point:
T₀ =100°C = 373.15K and p₀ = 1atm
Therefore the saturation vapor pressure at
T = 350°C = 623.15K
is
p = 1atm ·exp{(40700J / 8.314472kJ/mol)·(1/373.15K - 1/623.15K)} = 193 atm
hope this helps
It's a chemical change. In synthesis you add compounds which form new ones. This means that it cannot be a physical or phase change because you form something new. Not all synthesis and decomposition reactions use nuclear energy therefore it is a chemical change.
Answer:
Ammonia accepts a proton from water
Explanation:
Let us quickly remind ourselves of the Brownstead-Lowry definition of an acid. According to Brownstd-Lowry, an acid is any substance that donates hydrogen ions while a base is any substance that accepts hydrogen ions. The hydrogen ion is also known as a proton.
If we look at the behaviour of ammonia in water;
NH3(g) + H2O(l) ----> NH4^+(aq) + OH^-(aq)
We can easily see that ammonia accepts a proton from water (this makes it a Brownstd-Lowry base) and the hydroxide ion is formed in the process. Water functions as the proton donor here.