a crystal of chalcanthite (cuso4⋅5h2o) dissolves in a large tank of pure water according to the following equation:

cuso4⋅5h2o(s) → cuso4(aq) + 5h2o(l)

estimate the rate at which the crystal dissolves by calculating the flux of cuso4 from the crystal surface to the bulk solution. assume that molecular diffusion occurs through a liquid film uniformly 0.01 mm thick surrounding the crystal. at the inner side of the film adjacent to the crystal surface the solution is saturated with cuso4 while at the outer side of the film the solution is virtually pure water. the solubility of chalcanthite in water at 275 k is 24.3 g of crystal/100 g of water, and the density of the corresponding saturated solution is 1140 kg/m3. the diffusivity of cuso4 in dilute aqueous solution at 275 k can be estimated as 3.6×10-10 m2/s.

he uptake of drugs from the intestine is often strongly influenced by diffusion. for example, consider a water-insoluble steroid for treating inflammation that is solubilized in aggregates of detergent molecules, called micelles. these micelles, aggregates of 80 soap molecules, have a molecular weight of 24,000, a diameter of 2.6 nm, and a charge of -27. the positively charge ions (counterions) in this system are na".

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.

a is the correct answer