0:06 so we're going to begin section 6.3 and
0:09 the topic of our uh this chapter is
0:12 molarity molarity is a measure of the
0:15 concentration of a solution so your
0:17 learning objectives for this section are
0:19 to be able to describe the fundamental
0:21 properties of solutions
0:24 calculate solution concentrations using
0:26 molarity and perform dilution
0:29 calculations using the dilution equation
0:32 in the preceding sections we focused on
0:34 the composition of pure substances
0:37 however mixtures that is samples that
0:39 contain two or more substances
0:41 physically combined or more commonly
0:43 encountered in nature than pure substances
0:44 substances
0:46 similar to a pure substance the relative
0:48 composition of a mixture plays an
0:50 important role in determining its properties
0:57 so here's a familiar solution sugar is
0:58 one of the many components in the
1:01 complex mixture known as coffee once all
1:03 the sugar dissolves and the coffee is
1:07 stirred we have a homogeneous mixture or
1:08 a solution
1:10 the higher the concentration of sugar
1:19 another example from foods is distilled
1:21 white vinegar so distilled white vinegar
1:24 is simply a solution of acetic acid in water
1:30 so Solutions occur frequently in nature and
1:31 and
1:34 um Solutions is is just another term for
1:36 a homogeneous mixture so homogeneous
1:39 mixture has a uniform composition and
1:42 properties throughout its entire volume
1:45 relative amount of a given uh the
1:47 relative amount of a given solution
1:55 so there's really two components to a
1:58 solution there's the solvent which I
2:00 will typically call just the major
2:02 component it's the component with a
2:04 concentration that is significantly
2:05 greater than that of all the other
2:09 components and then there's the solute
2:11 which is the component that is typically
2:13 present at a much lower concentration
2:20 um Solutions we often think of solutions
2:22 as being liquids but they can also be
2:24 solids or gases so for instance
2:26 stainless steel is a solid solution
2:30 where iron is a solvent that is it's the
2:32 major component and chromium is the
2:35 solute or minor component
2:39 solid Solutions of metals are often
2:41 called alloys
2:44 air is a um a gaseous solution where
2:47 nitrogen is the solvent and oxygen and
2:55 so molarity is a measure of the number
2:59 of moles of solute in one liter of the solution
3:00 solution
3:04 so molarity has units then of moles of
3:08 solute divided by liters of solution
3:10 it's a very useful concentration unit
3:20 here's an example a 355 milliliter soft
3:24 drink sample contains 0.133 mole of
3:26 sucrose or table sugar
3:28 what is the major concentration of
3:31 sucrose in the beverage
3:34 so to calculate we simply divide the
3:37 number of moles of sucrose
3:40 by the number of liters of solution
3:43 since we were given milliliters we have
3:45 to first convert milliliters to liters
3:49 using this conversion factor here and then
3:50 then divide
3:52 divide
3:56 0.133 mole by the volume in liters and
