A cord is used to vertically lower an initially stationary block of mass m kg at a constant downward acceleration of g/4. the bl
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This is a straightforward dilution calculation that can be done using the equation
where <em>M</em>₁ and <em>M</em>₂ are the initial and final (or undiluted and diluted) molar concentrations of the solution, respectively, and <em>V</em>₁ and <em>V</em>₂ are the initial and final (or undiluted and diluted) volumes of the solution, respectively.
Here, we have the initial concentration (<em>M</em>₁) and the initial (<em>V</em>₁) and final (<em>V</em>₂) volumes, and we want to find the final concentration (<em>M</em>₂), or the concentration of the solution after dilution. So, we can rearrange our equation to solve for <em>M</em>₂:
Substituting in our values, we get
So the concentration of the diluted solution is 0.05875 M. You can round that value if necessary according to the appropriate number of sig figs. Note that we don't have to convert our volumes from mL to L since their conversion factors would cancel out anyway; what's important is the ratio of the volumes, which would be the same whether they're presented in milliliters or liters.
Answer:
The answers to the questions are;
a. The entropy of sublimation for carbon dioxide (the system) is
134.07 J/Kmol.
b. The entropy of the universe for this reversible process is 376 J/K.
Explanation:
Entropy of sublimation is the entropy change experienced following the transformation of a mole of solid to vapor at the temperature where the sublimation is taking place
a. We note that the mass of the solid CO₂ = 389 g
Molar mass of CO₂ = 44.01 g/mol
Number of moles of CO₂ in the sculpture = Mass/(Molar mass)
= (389 g)/(44.01 g/mol) = 8.84 Moles
Entropy of sublimation is given by
ΔS =
- S
=
Where:
ΔH = 26.1 KJ/mol
T = Temperature = –78.5°C = 194.65 K
Therefore the amount of heat required to cause the 389 g of dry ice to sublime = 26.1 KJ/mol × 8.84 Moles = 230.695 KJ
Therefore the entropy of sublimation = ΔS =
= 1.185 KJ/K
= 1185 J/K = 1185/8.84 J/Kmol = 134.07 J/Kmol
b. The entropy of the universe is given by;
ΔS =
+ ΔS
If the heat absorbed by the system is the same as the heat given off by the surrounding, then we have;
ΔS =
=1.185 KJ/K - = 1.185 KJ/K - 0.809 KJ/K = 0.376 KJ/K
= 376 J/K.