NANDANI KUMARI

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Illustrate with an example what is meant by standard free energy change of formation of compound State the relation between standard free energy change and equilibrium constant of a chemical reaction.

Standard free energy of formation is the free energy change that occurs when 1 mole of a compound forms from its component elements at standard conditions.

The standard change in free energy, ΔG, for a reaction is related to its equilibrium constant, K, by the equation ΔG = -RTlnK.

Calculate the free energy change and entropy change per mole when liquid water boils against 1 atmospheric pressure [ for water d H = 2.0723 kj/gm]

$Δ H_{v a p} o f w a t e r = 2.0723 18 = 37.30 K J m o l^{1}$

$Δ S_{v a p} = \frac{Δ H_{v a p}}{T_{b}} = \frac{37.30 K J m o l^{1}}{373 K} = 0.1 k J m o l^{1} K^{1}$

$Δ G_{v a p} = Δ H (k J m o l^{1}) T (K) Δ S (k J m o l^{1})$

$= 37.30 373 0.1 = 0$

Define the following terms:[a] State variables of asystem [b] Internal energy of system

State variables of a system are physical quantities whose change in value only depends on initial and final state of system and doesn't follow on the path which system follows during change.

Internal Energy of a system is a sum of all kinds of energies possessed within it.

When caustic soda is added to an aqueous solution of copper sulphate, a blue precipitate of Cu(OH)2 is obtained. How will you separate Cu(OH)2 from the mixture ?

Write the action of it upon I)moist air II) conc. H₂SO

i. Action with moist air: After long exposure to moist air, a green layer of its basic carbonate is formed over it.

2Cu + H₂O + CO₂ + O₂ ---------------> CuCO₃.Cu(OH)₂

ii. Action of Conc. H₂SO₄: When heated with conc.H₂SO₄Sulphur dioxide gas is formed.

Cu + 2H₂SO₄-------------------> Cu(NO₃)₂ + 2NO₂ + 2H₂O

how is metal copper extracted from its pyrite ore?

It can be extracted from copper pyrite which goes through the following step:

1. Crushing and pulverization:The big size of the ore is crushed and it is changed into a fine powder then it is taken for concentration.

2. Concentration:The obtained powder ore is concentrated by the froth floatation process. Then it is taken for roasting.

3. Roasting:It is then heated strongly in a reverberatory furnace. The volatile impurities such as sulphur, arsenic, etc are removed and pyrite ore is converted...

Write a note highlighting the important fact about the chemistry of blue vitriol.

USES OF BLUE VITROL

Antiseptic agent

In electroplating processes.

Antifungal agent for topical use

Treatment of copper deficiency

Etching - Copper sulfate is also used to etch zinc plates for intaglio printmaking.

Dyes - Copper sulfate can also be used as a mordant in vegetable dyeing. It often highlights the green tints of the specific dyes.

Copper sulfate is used to test blood for anemia. The blood is tested by dropping it into a solution of copper sulfate of known specific gravity.

Copper sulfate...