Answer:
D) Mn + Ni2+ ⇒ Mn2+ + Ni
Explanation:
A spontaneous process can occur in a specific direction without requiring any energy input from external sources. Such reactions happen naturally. In these spontaneous processes, the entropy change is positive (ΔS), the enthalpy change is negative (ΔH), and most importantly, ΔG (the change in free energy) is negative.
To identify which reaction is spontaneous, we analyze the electrode potentials of the involved species. The species with a more negative reduction potential can displace the other from its aqueous solution. In this case, since the reduction potential for Mn^2+ is -1.19 V compared to nickel's -0.25 V, manganese will thus naturally displace Ni^2+ from solution as indicated in the solution above.
The enthalpy of hydration for copper sulfate is -1486.62 kJ/mol, indicating that 1486.62 kJ of energy is absorbed by a mole of copper sulfate during its hydration. Step 1: Calculate the energy released per mole of dissolved substance (Eq. 1). If 0.102 moles release 55.51 kJ, then 1 mole corresponds to 541.85 kJ/mol. Therefore, ΔH = -541.85 kJ/mol. Step 2: Identify the energy absorbed by dissolved substance (Eq. 2). When 0.101 moles absorb 95.31 kJ, 1 mole will absorb 944.77 kJ/mol, thus ΔH = 944.77 kJ/mol. Step 3: Subtract Eq. 2 from Eq. 1. Thus, ΔH = -541.85 kJ/mol (Eq. 1) and ΔH = 944.77 kJ/mol (Eq. 2), leading to ΔH = -541.85 - 944.77, so ΔH = -1486.62 kJ/mol.
Response:
a. The return of the process fluid after it has been cooled, condensed, or heated in a distillation column or packing.
b. should remain stable at elevated temperatures
should not generate additional by-products
should be chemically inert
c. expressed as a range
d. determined by conducting a series of measurements
e. impurities cause substances to melt at lower temperatures.
Explanation:
a. In a reflux system, the condensate is returned to the initial flask or boiler. This keeps the process fluid at a constant temperature without needing more fuel while increasing the molar fraction of the distillate (which enhances product purity).
b. A solvent needs to be stable and should not participate in side reactions that produce unwanted by-products, ideally remaining inert at elevated temperatures.
c. It is advisable to report melting points as a range since various factors influence the melting point in experimental setups.
d. Melting points can be ascertained through a series of graphical measurements.
e. Impurities reduce the melting point of substances.
a)
26C5 -> 26 ways to select 5 items
b)
15C1 × 11C4
c)
11C1 × 15C4
d)
11C2 × 15C2
e)
11C4
or
15C4
