Chapter 111 3. Units of Concentration unitless Definition same
Chapter 112 Advantages/disadvantages of each (read only; no lecture)
Chapter 113 Example problems 1. Determine the molarity of a 0.258 m solution of glucose given that the solution’s density is 1.0173 g ml -1 and that the molar mass of glucose is 180.2 g. first, write down definitions: molarity is moles solute per liter solution; molality is moles solute per kg solvent; density is mass solution per volume solution assume some amount of solution to start: in this case 0.258 moles glucose and 1 kg water we want: moles solute/liter solution so we have 0.258 moles solute
Chapter 114 get the total volume of the solution - glucose plus water solve for the molarity mass sol’n volume sol’n
Chapter 115 2. Determine the molality of a 0.500 M solution of acetic acid (molar mass 60.02 g) with a density of 1.0042 g ml -1. Again, write down the units and their definitions. Start by assuming 1 L of solution and thus 0.500 moles acetic acid determine the mass of the solution from the density times the volume determine the mass of water (in kg) by subtraction (subtract the mass of the acetic acid from the mass of the solution) solve for the molality
Chapter 116 3. Describe how 1.50 L of a 12.0% KBr solution is made if the solution density is 1.10 g ml -1. In other words, determine the mass of KBr and the mass of water to be mixed together. Write out the units and their definitions 1.50 L or 1500 ml of solution are required; determine the total mass of solution required (HOW?). Of the total mass of solution, how much must be KBr? Determine the mass of water necessary (HOW?).
Chapter 117 total mass solution mass KBr mass water dissolve 198 g KBr in 1452 g water