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
Answer:
ΔH°(f) = -110.5 Kj/mole (exothermic)
Explanation:
C + 1/2O₂ => CO
This is asking for the 'Standard Heat of Formation (ΔH°(f)* for carbon monoxide (CO). Values for many compounds can be found in the appendix of most college general chemistry text books. From Ebbing & Gammon, 11th edition, General Chemistry, Appendix C, page 8A.
*Standard Heat of Formation by definition is the heat gained or lost on formation of a substance (compound) from its basic elements in standard state.
The ΔH°(f) values as indicated are found in the appendix of most college chemistry texts. By choosing any compound, one can determine the standard heat of formation equation for the substance of interest. For example, consider Magnesium Carbonate; MgCO₃(s).The basic standard states of each element is found in the Appendix on Thermodynamic Properties for Substances at 25°C & 1 atm. having ΔH°(f) values = 0.00 Kj/mole. All elements in standard state have a 0 Kj/mol. See appendix and note that under the ΔH°(f) symbol some substances have 0.00 Kj/mol values. The associated element will be in basic standard state,
Standard Heat of Formation Equation for formation of Magnesium Carbonate;
Mg°(s) + C°(gpt)* + 3/2O₂(g) => MgCO₃(s) ; ΔH°(f) = -1111.7 Kj/mole
* gpt => graphite
Answer:
Ratio of Vrms of argon to Vrms of hydrogen = 0.316 : 1
Explanation:
The root-mean-square speed measures the average speed of particles in a gas, and is given by the following formula:
Vrms = 
where R is molar gas constant = 8.3145 J/K.mol, T is temperature in kelvin, M is molar mass of gas in Kg/mol
For argon, M = 40/1000 Kg/mol = 0.04 Kg/mol, T = 4T , R = R
Vrms = √(3 * R *4T)/0.04 = √300RT
For hydrogen; M = 1/1000 Kg/mol = 0.001 Kg/mol, T = T, R = R
Vrms = √(3 * R *T)/0.001 = √3000RT
Ratio of Vrms of argon to that of hydrogen = √300RT / √3000RT = 0.316
Ratio of Vrms of argon to that of hydrogen = 0.316 : 1
The anode is charged positively. Oxidation happens on the anode.
For example,
(anode +) Zn - 2e⁻ = Zn²⁺
In very basic terms alchemy is magic and chemistry is scientific.
