Properties of Solutions Use section 15 and your textbook glossary to complete this worksheet

Transcription

1 Part 1: Vocabulary Properties of Solutions Use section 15 and your textbook glossary to complete this worksheet A solution is a mixture The solvent is the medium in a solution. The particles are the solute. Solvents and solutes may be, or. An electrolyte is a compound that an when it is in an aqueous solution or in the state. A nonelectrolyte is a compound that does not an in either aqueous solution or the state. Solubility refers to the amount of a substance that in a given quantity of at specified conditions of and to produce a solution. Solvation is the process by which the and ions of an ionic solid become surrounded by molecules. Part 2: Solubility Substances that dissolve most readily in water include compounds and covalent molecules. Nonpolar covalent molecules, such as and compounds found in, and do not dissolve in water. However, and will dissolve in gasoline. In some ionic compounds, the attraction among the ions in the crystals are than the attractions exerted by. These compounds are therefore nearly. ( ) and ( ) are examples of nearly ionic compounds. As a rule, solvents such as water dissolve compounds and compounds; solvents, such as gasoline dissolve compounds. This relationship can be summed up in the expression dissolves. Circle the factors below that would help to dissolve a solid in a liquid Circle the factors below that would help to dissolve a gas in a liquid Increase temperature of the solution Stirring/Agitation Increase temperature of the solution Stirring/Agitation Decrease temperature the solution Increase pressure Decrease temperature the solution Increase pressure Break up the solid Decrease pressure Decrease pressure Page 1

2 Calculations of Solution Concentration California State Standard: Students know how to calculate the concentration of a solute in terms of grams per liter, molarity, parts per million, and percent composition. Molarity describes the concentration of a solution in moles of solute divided by liters of solution. Masses of solute must first be converted to moles using the molar mass of the solute. This is the most widely used unit for concentration when preparing solutions in chemistry and biology. The units of molarity, mol/l, are usually represented by a scripted capital M. Calculate the concentration, in moles of solute per liter of solution, of each of the following: Step #1 - Convert grams of solute to moles of solute: 10 g NaOH 1mol NaOH 0.250mol NaOH 40 gnaoh = Step #2 Divide moles of solute by liters of solution: mol NaOH = 0.125M NaOH 2 L 1) 20 grams of NaOH is dissolved in enough water to make 1 liter of solution 2) 45 grams of glucose, C 6 H 12 O 6 is dissolved in enough water to make liters of solution 3) 116 grams of KF is dissolved in enough water to make 4 L of solution 4) 63 grams of HNO 3 is dissolved in enough water to make 100 liters of solution 5) 280 grams of CaO is dissolved in enough water to make 10 L of solution Percent composition is the ratio of one part of solute to one hundred parts of solution and is expressed as a percent. Determine the mass of solute and solution and then divide the mass of the solute by the total mass of the solution. This number is then multiplied by 100 and expressed as a percent. In dilute water solutions, we can assume that 1 ml of water-based solution has a mass of 1 gram, so 1 liter of solution has a mass of 1000 grams. 10 gnaoh x 100= 0.5% NaOH 2000 g solution 6) 20 grams of NaOH is dissolved in enough water to make 1 liter of solution 7) 45 grams of glucose, C 6 H 12 O 6 is dissolved in enough water to make liters of solution 8) 116 grams of KF is dissolved in enough water to make 4 L of solution 9) 63 grams of HNO 3 is dissolved in enough water to make 100 liters of solution 10) 280 grams of CaO is dissolved in enough water to make 10 L of solution Page 2

3 Molarity Calculations Work Space 1.) 2.) 3.) 4.) 5.) Percent Composition Work Space 6.) 7.) 8.) 9.) 10.) Page 3

4 Parts per million (ppm), is a ratio of parts of solute to one million parts of solution, and is usually applied to very dilute solutions. It is often found in reports of concentration of water contaminants. To calculate parts per million, divide the mass of the solute by the total mass of the solution. This number is then multiplied by 10 6 and expressed as parts per million (ppm). In dilute water solutions, we can assume that 1 ml of water-based solution has a mass of 1 gram, so 1 liter of solution has a mass of 1000 grams. ***Notice that calculations of ppm are the same as percent composition, except that you multiply by 1 million instead of by gnaoh x 6 10 = 5000 ppm NaOH 2000 g solution 11) 20 grams of NaOH is dissolved in enough water to make 1 liter of solution 12) 45 grams of glucose, C 6 H 12 O 6 is dissolved in enough water to make liters of solution 13) 116 grams of KF is dissolved in enough water to make 4 L of solution 14) 63 grams of HNO 3 is dissolved in enough water to make 100 liters of solution 15) 280 grams of CaO is dissolved in enough water to make 10 L of solution Grams per liter represent the mass of solute divided by the volume of solution, in liters. This measure of concentration is most often used when discussing the solubility of a solid in solution. Calculate the concentration, in grams per liter of solution, of each of the following: 10 grams 5 g/ L 2 Liters = 16) 20 grams of NaOH is dissolved in enough water to make 1 liter of solution 17) 45 grams of glucose, C 6 H 12 O 6 is dissolved in enough water to make liters of solution 18) 116 grams of KF is dissolved in enough water to make 4 L of solution 19) 63 grams of HNO 3 is dissolved in enough water to make 100 liters of solution 20) 280 grams of CaO is dissolved in enough water to make 10 L of solution Page 4

5 Parts Per Million (ppm) Calculations Work Space 1.) 2.) 3.) 4.) 5.) Grams / L Calculations Work Space 6.) 7.) 8.) 9.) 10.) Page 5

6 Name: Mr. Leal Date: Per: 1/10/2014 Solution Chemistry Molarity How to Make a Solution Vocab: 1. What is the purpose of a Volumetric Flask? In order to make a solution, you must first know how many grams of solid needed. To solve for this, you put the volume of your desired solution first and convert it to L (if needed), then multiply it by the molarity. Lastly, you multiply this by the molar mass of the solute. Please fill in the fractions describing the setup: x x x = grams solid Example Determine the number of grams of a sodium chloride needed to make 900. ml of M NaCl solution: 900. ml x 1 L x mol NaCl x 58.5 g NaCl = 26.3 g NaCl 1000 ml 1 L 1 mol NaCl Problems: 1. Determine the number of grams of potassium chloride needed to make 250. ml of M solution. 2. Determine the number of grams of calcium hydroxide needed to make 475. ml of 1.25 M solution. 3. Please write all procedures to make a 500 ml solution of 0.65 M NaOH. Page 6 Solution Chem - Molarity 2a - Make Solution.doc