Concentrations Express the concentrations of solutions in terms of percent by mass, percent by volume, parts per million and molarity. Use Table T to calculate problems relating to concentrations. Describe the preparation of a solution given the molarity.

Aim How can we use mathematics to understand the concentrations of solutes? Essential Questions: 1.In what ways can we describe the concentrations of solutions? 2.How can we use reference Table T to calculate parts per million and molarity? 3.How do we describe the preparation of a solution, given the molarity? Explain. Key Words solute, solvent, dilute, percent by volume, percent by mass, parts per million and molarity.

Picture This You are in a lab and your petri dish broke, spreading cultured bacteria all over the table! You head over to the supply closet to get some alcohol so you can clean up and destroy the bacteria before they spread. 2 % 90 % Which bottle would you take? What do the percentages represent?

When it Comes to Solutions, Concentration is Important! If you are going for a surgery, you would want your anesthesiologist to administer the appropriate concentration of anesthesia to you! If you are going for a swim at an indoor pool, you would want the maintenance crew to mix the appropriate concentration of chlorine in the pool. Too much and your hair may fall out. Too little and you may be swimming in bacteria! We are going to spend the next two lessons discussing the different ways concentration can be represented in a solution.

Sneak Peak  Percent by Mass  Percent by Volume  Parts Per Million  Molarity

What is the Formula for Calculating Percentages? Using terms such as “part” and “whole,” please write down the generic formula for calculating percent.

Percent Concentration Formulas Mass Percent Concentration Volume Percent Concentration

Practice 1.A student dissolves 25.0 grams of glucose in 475 grams of water. What is the mass percent concentration of the glucose solution?

Practice 2.A solution is prepared by dissolving 90 milliliters of pure hydrogen peroxide in enough water to make 3000 milliliters of solution. What is the volume percent concentration of the hydrogen peroxide solution?

What if I need to know the concentration of a very dilute substance whose concentration turns out to be a tiny fraction of a percent?

POISONOUS MATERIAL H2S? DISSOLVED OXYGEN IN WATER

Parts per Million Parts per Million (ppm) Scientists express the maximum allowable concentrations of toxic or cancer-causing substances in ppm. Ex. The maximum allowable concentration of arsenic in drinking water is 0.05 ppm, which means 5 grams of arsenic per 100,000,000 grams of drinking water.

Practice 1.A certain gas has a concentration in water of 2 grams per 100 kilograms of water. What is the concentration of the gas in parts per million?

III. Concentration Calculations A.The concentration of a solution may be expressed as A.Percent by Mass a.Percent by Volume a.Parts per Million (ppm) b.Molarity (M)Notes