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Solute concentration is defined as the amount of the solutepresent in a given volume of solution. The concentrations ofsolutes in a solution are key to their ability to producephysiological actions. One measure of the amount of a substance isits mass expressed in grams. The unit of volume in the metricsystem is a liter (L). The concentration of a solute in a solutioncan then be expressed as the number of grams of a substance presentin any one liter of solution (g/L). A comparison of theconcentrations of two different substances on the basis of thenumber of grams per liter of solution does not directly indicatehow many molecules of each substance are present. Thus,concentrations are expressed based upon the number of solutemolecules in solution, using a measure called the molecular weight.One mole (mol) of a compound is the amount of the compound in gramsequal to its molecular weight. One mole of solute dissolved in aliter of water is known as a 1 molar solution (1 mol/L).

To practice calculating molecular weight and examining therelationship between volume and solute variations, complete thefollowing exercises.

First, calculate the molarity of a 2 L solution with fivedifferent amounts of solute (20, 40, 60, 80, and 100 g). The solutefor this activity is glucose with a molecular weight of 180daltons. Round all of your calculations to the nearest hundredthfor credit.

Then plot each of these data points by clicking to select theamount of solute from the \"Tools\" section at right and thenclicking on the exact location on the graph corresponding to yourcalculations. If you wish to change your data point on the graphafter first placement, you can double click the data point andadjust the values.

Second, calculate the molarity for five different solutionvolumes (0.5, 1.0, 1.5, 2.0, and 2.5 L) each with 80 grams ofsolute. The solute for this activity is glucose with a molecularweight of 180 daltons. Round all of your calculations to thenearest hundredth for credit.

Then plot each of these data points by clicking to select thefinal total volume from the \"Tools\" section at right and thenclicking on the exact location on the graph corresponding to yourcalculations. If you wish to change your data point on the graphafter first placement, you can double click the data point andadjust the values.