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Explain why molality is used for boiling point elevation and feezing point depression calculations and molarity is used for osmotic pressure calculations?
Molality is independent of temperature, so when you are trying to find changes in boiling and freezing points you need something that will stay constant regardless of the change in temperature. Molarity is temperature dependent and also is based on the volume of a solution, both of which are needed to calculate pressure using the ideal gas law, PV=nRT. Osmotic pressure is similar but we substitute the number of moles of the solution and the volume by using the molarity, you cannot do this with molality, since it is dependent on mass, not volume.
What else can I help you with?
Calculate the molarity of a 10 percent aqueous solution of HCl?
molarity = mol / litre The concentration is 10% HCl in water, assuming this is expressed in w/v (weight to volume) as this is the normal way. The density of 10% HCl is unknown but will be estimated to be the same as water (although slightly incorrect), since no data is given. 1 L of which 10% are HCl is assumed to weigh 1000 grams. 10% HCl x 1000g = 100g of HCl. 100g of HCl is present in 1 L. The mw of HCl = 36.5g/mol, 100g/(36.5g/mol) = 2.74mol is present in 1 L. The molarity is 2.74mol / 1 L = 2.7 M (two significant figures) (Looking up hydrochloric acid in wikipedia tells us that the density of a 10% solution is actually 1048g/L and the actual molarity becomes 2.87M. The calculated number was close enough, but it shows that the density is important. Molality on the other hand is mol/kg, so with molality we can skip the unknown density problem. For practical purposes, molarity is still the mostly used one, because volume is easier to measure than weight in the laboratory when handling toxic solvents that are unhealthy to inhale.)
What is the molarity of a solution that contains 202 mol KCl in 7.98 L solution?
Molarity is moles per litre. Therefore if you divide by 7.98 you get it as moles per litre, i.e. molar. 202/7.98 is 25.31 molar.
What is the molarity of pure liquid benzene?
Molarity is a concentration unit of solutions, pure benzene is not a solution so this term is meaningless for a pure liquid. In other words: Molarity of a solution is a numerical way of saying exactly how much solute is dissolved in a solvent .Molarity is equal to the moles of solute divided by the liters of solution. Molarity of a solution can be calculated by using the following formula: M= moles of solute/liters of solution
What is the molarity of a 3.45L solution that contains 0.491 mols of sodium sulfate?
The molarity of the solution can be calculated using the formula Molarity (M) = moles of solute / liters of solution. Molarity = 0.491 moles / 3.45 liters = 0.142 M. So, the molarity of the solution is 0.142 M.
What is the molarity of a solution where 4.00 moles of Potassium Chloride is dissolved in 3.00 L of solution?
The molarity of a solution given by the number of moles divided by the volume it contains. Hence, the molarity of KCl is 4.00/3.00 = 1.33 mol/L.
Why do we have to use molality for our calculations, instead of the more common unit of molarity?
Molality is used for calculations instead of molarity because it is a more accurate measure of concentration. Molarity can change with temperature, while molality remains constant. This makes molality more reliable for certain calculations, especially those involving changes in temperature.
How are concentrations in solutions quantified?
through molarity,molality, normality. through molarity,molality, normality.
Why molarity is better than molality?
Molarity is better than molality for many applications because it is more commonly used and easily measured in the laboratory. Additionally, molarity accounts for volume changes with temperature, whereas molality does not. This makes molarity more versatile for a wider range of experimental conditions.
Why is molality used in determining the freezing point of a solution?
Molality is used in determining the freezing point of a solution because it accounts for the mass of the solvent, which affects the colligative properties of the solution. The freezing point depression is directly proportional to the molality of the solute particles in the solvent, making molality a more accurate measure for calculating the freezing point depression compared to other concentration units like molarity.
How do you solve freezing point depression problems when given only the molarity?
Calculating the freezing point depression of a solvent requires three pieces of information: 1) the molal freezing point depression of that solvent; 2) the molality of the solution; 3) the number of distinct entities produced in solution per molecular formula unit of solute. Hopefully you meant molality instead of molarity (if the solvent is water and it's a dilute solution, assuming that molality = molarity isn't a bad approximation). I suspect you've been told what 1 and 3 are (or been given enough information to figure them out) but simply didn't mention it; otherwise you're pretty much boned.
Is molality or molarity expressed in grams of solute instead of moles of solute?
Molality is expressed in grams of solute per kilograms of solvent, while molarity is expressed in grams of solute per liter of solution. Both molality and molarity are concentrations that measure the amount of solute in a given amount of solvent, but they are calculated differently.
Is it molality greater or molarity greater why?
"MolaRity" is the correct spelling for mass per amount solution."MolaLity" is the correct spelling for mass per amount solvent.The conversions of molality, b, to and from the molarity , c,for one-solute solutions are:c = ρ.b / [1 + b.M]andb = c / [ρ -c.M]where ρ is the mass density of the solution, b is the molality, and M is the molar mass of the solute.
How are molarity and molality similar?
Both express moles of solute in the numerator.
When does molarity and molality become equal?
In dilute solutions... ie closer a solution is to pure water the closer molality and molarity come to equalling each other. This is because the molality uses mass and molarity uses volume, the ratio of these two (mass and volume) is density, and water has the density of 1 therefore the mass and volume are equal to each other. THEREFORE calculating the molarity of water is the same as calculating the molality of water.
Moles of a solute per kilogram of a solvent?
This is the definition of molality, which is a concentration measure used in chemistry to express the amount of solute in a solution per kilogram of solvent. It is denoted by a lowercase "m" and is calculated by dividing the moles of solute by the mass of the solvent in kilograms.
Why you use molality in biology experiments?
Molality is used when temperature varies in an exothermic or endothermic reaction because it is not dependent on temperature or pressure. Molality does not depend on tempratute whereas molarity does.
What is the difference between the symbols used to represent molarity and molality in a solution?
The symbol used to represent molarity is "M," while the symbol used to represent molality is "m." Molarity is the concentration of a solute in a solution in terms of moles of solute per liter of solution, while molality is the concentration of a solute in a solution in terms of moles of solute per kilogram of solvent.
