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When The Solute Is A Liquid It Is More Convenient To Express The Solution Concentration As A

Hey can anyone finish this science sentence?

A1.
The most common way to express concentration is on the basis of the weight of solute per unit weight of solvent. For example, a salt solution may be prepared by dissolving 1.64 grams of sodium chloride in 100 grams of water. The concentration of this solution could also be expressed as 0.0164 grams of NaCl per 1 gram of water, or as 16.4 grams of NaCl per 1,000 grams of water. Thus, a statement of the concentration of a solution does not imply anything concerning the amount of solute or the amount of solvent present, but rather gives the ratio of solute to solvent in terms of some convenient (and arbitrary) units. Because the weight of a sample of a liquid is usually more difficult to determine experimentally than its volume, a practical unit of concentration is the weight of solute in a given volume of the solution; for example, a sugar solution may contain 50 grams of sugar per 100 milliliters of solvent. The answer is percent changes.

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A.2 Increases.

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Ways to calculate molality?

Molality = moles of solute / kilograms of solution

Why molality is preferred over molarity in expressing the concentration of solution?

Molarity is number of moles per unit volume of the solution and molality is number of moles per unit mass of solvent.Volume is temperature dependent where as mass is constant at all temperatures.So, molality remains constant but molarity changes with temperature. Hence , molality is preferred over molarity.

Why is the molecular mass of polymers determined by osmotic pressure and not by other colligative properties?

In order to determine the molecular weight of polymers it is necessary to dissolve the polymer in an appropriate solvent and begin with dilute solution. The colligative properties are (i)RLVP (ii) Elevtion of boiling point (iii) Depression of freezing point (iv) Osmotic pressure.where, Δ Tb , Δ Tf , and π are boiling point elevation, freezing point depression and osmotic pressure, ρ is the density of the solvent, Δ Hν and Δ Hf are respectively the latent heat of vaporization and of fusion of the solvent per gram, c is the polymer (solute) concentration in g/cm3 and M is the solute molecular weight. Very low observed temperature differences (of the order of 10-3 0C) for low finite concentrations of a polymer of the molecular weight range of ≥ 20,000 and lack of development of equipments for ebulliometric and cryoscopic measurements have turned them unattractive and less useful.The osmotic method is in more wide use than other colligative techniques as because the osmotic response is of a magnitude that is easily observable and measurable, even though success of this method is contingent upon availability of prefect osmotic membranes.

What is the different between v/v and w/v?

V/v is a molar solutionW/v is a molal solution

Why we are using normality, molarity and molality?

All the 3 terms are different. Let us first defineMolarity: It is the concentration of a solute expressed in terms of moles per liter. If the molarity of a NaCl solution is 2 M, it means that 2 moles of NaCl are present in 1 liter of solution.Molality: It is also the concentration of a solute, but expressed in terms of moles per kg of solvent. It may seem unnecessary to put mass instead of volume for the solvent. However, there is a specific reason for that. Liquids have different volumes at different temperatures. For example, take 1 kg of water at 25 C and it will be 1 liter. Heat the water upto 50 C (assuming minimal evaporation) and now its volume will slightly increase. In order to avoid errors in concentration, molality is used since mass of the solvent will not change with temperature.Normality: This is an interesting concept. I remember that in chemistry practicals, we used to express the concentration of acids and bases in terms of Normality. Why was that ? I simply did not understand it at that time. Now it seems very simple.Suppose you take 100 ml of 0.1 M NaOH, you can neutralize it completely with 100 ml of 0.1 M HCl. However, you will only require half the volume of H2SO4 to completely neutralize it. Why is that ? It is because 100 ml of 0.1 M NaOH contains 0.01 moles of OH- ions which can be neutralized by an equivalent amount of H+ ions. Since 100 ml of 0.1 M HCl contains 0.01 moles of H+ ions, it will completely neutralize the solution. But 100 ml of 0.1 M H2SO4 contains 0.02 moles of H+ ions which is twice the required amount. Hence, only half of the amount is required to neutralize the solution. So 0.1 M HCl solution is equivalent to 0.1 N HCl solution while 0.1 M H2SO4 solution is equivalent to 0.2 N H2SO4 solution.REMEMBER THIS - 1 N acid of a given volume can be neutralized by 1 N base of the same volume but it is not always apply for 1 M acid and 1 M base.Hence, acids and bases are expressed in terms of Normality in order to maintain uniformity in calculating their amount required in titrations.Edit : For strong acids, complete dissociation of ions is assumed. For weak acids, the dissociation constant must be accounted for.Please do read my blog Breathe by Words for more information.