This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. Finally, divide the grams of your substance by the Molar Mass. wikiHow's Content Management Team carefully monitors the work from our editorial staff to ensure that each article is backed by trusted research and meets our high quality standards. Look up the density of salt either in a textbook or online and solve the formula for m. In this case, the density of salt is 2.16 g/mL. wikiHow is where trusted research and expert knowledge come together. Michael has worked for an aerospace firm where he was in charge of rocket propellant formulation and is now a college instructor. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. So in this example, 2 L + 1.6 mL = 2,000 mL + 1.6 mL = 2,001.6 mL. In this example, M = (0.45 mol)/(0.4 L) = 1.125 M. Divide the value you just obtained by the molar absorptivity (e) of the particular chemical in your solution. Under the Le Chatelier's principle, the more concentrated one will have faster reacting time due to the fact that the more concentrated one has more molecules of that substance, leading to the ultimate truth that the chances of molecules meeting each other is bigger. It happens when the metal reacts w/ the acid so quickly that the metal forms a salt, preventing the further reaction to the acid. Hemera Technologies/PhotoObjects.net/Getty Images. Finally, divide the solvent by the solute to find the concentration of the solution. For example, if your solute is potassium hydroxide (KOH), find the atomic masses for potassium, oxygen, and hydrogen and add them together. If you have a small concentration, find the answer in parts per million (ppm) to make it easier to follow. We use cookies to make wikiHow great. Michael Judge has been writing for over a decade and has been published in "The Globe and Mail" (Canada's national newspaper) and the U.K. magazine "New Scientist." Multiply each side by 1.2 L to solve the mass in grams, so m = (1.2 L)(1,000 g/L) = 1,200 g. Add the mass of the cocoa powder to get 1,210 g. In our example, C = (10 g)/(1,210 g) = 0.00826. If you’re given the mass of the solute in your problem, write it down and be sure to label it with the correct units. Keep notes of your learning and work your way up to doing safe experiments at home (look for children's science experiment books in the library). This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. For a one centimetre (cm) path length, you would divide 0.699 by 1cm to obtain 0.699cm^-1. This article has been viewed 1,458,004 times. Write down the absorbance reading (A) of the solution for which you are calculating molarity. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. Here is the formula: P = M/V where P = density, M = mass and V = volume of the substance. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. Essentially, the molar absorptivity tells you how much light a solution of the chemical will absorb per unit concentration (mole) and unit path length (cm). To prepare 1,000 ml of the acetate buffer solution, 150 g of sodium acetate is dissolved in ~250 ml of distilled water.