– (n) the part of a solution present in the LEAST amount
(what is dissolved)
– (n) the part of a solution present in the greatest amount
(what does the
– (n) a homogeneous mixture containing a solute and a solvent mixed
Look at the two beakers (A and B) of pennies and macaroni as
an analogy of a solution (the pennies are the solute and the macaroni are the
type of mixture are these, really?
they solutions (consisting of a solute and a solvent)?
is the ratio of pennies to macaroni (write as a fraction
# of pennies / # of macaroni) of each?
you reach in to beaker A and take out what you grab, are you likely to grab a
penny? What about beaker B?
beaker has a greater “concentration” of pennies?
beaker has a more “dilute” “concentration” of pennies?
– (n) the measurement of how much solute there is in a solution (or
generally – the amount of substance found in a certain area or volume)
– (adj) a solution is said to be dilute if it has less solute.
– (adj) a solution is said to be concentrated if it has more solute.
In front of you there is a beaker of macaroni and pennies
with some extra pennies and macaronis in a bag.
two ways to concentrate (increase the concentration) the pennies in the beaker.
two ways to dilute (decrease the concentration) the pennies in the beaker.
(v) the process of adding more solvent to a solution or removing some of
– (v) The process of adding more solute or removing some of the solvent.
In Chemistry the concentration of a solution is most often
reported in Molar (M) units or moles of solute per liter of solvent (mol
example:We dissolve 58.44 g of NaCl
(salt) in a liter (L) of water in a bottle.
58.44 g NaClx1 mol NaCl=1 mol NaClora 1.000 M NaCl solution 1 L of H2O 58.44 g NaCl1 L H2O
We have created a 1.000 Molar
solution of NaCl or in other words a solution that contains 1 mole of NaCl per
liter of water.
In front of you there is a flask
that has a solution of 0.250 L of water with 14.61 g of NaCl dissolved in
is the molar concentration of the solution?
Chemists have special containers called volumetric flasks
for making solutions.The flasks have
one precisely measured volume mark on a skinny neck for accurate measurements
and a large bottom so that the solute can be swirled to dissolve.
Here are the steps Chemists take to make a solution:
your solvent (often water) until 2/3 of the large bottom is filled with water.
mass the appropriate amount of solute.
transfer ALL of the solute into the flask.
flask until all of the solute is dissolved (Be Careful not to spill any
of your solution or it will be inaccurate)
add solvent, swirling occasionally, until the meniscus of the solution reaches
the volume line.If you go over you must
start all over again.
one wanted to make a 2.00 molar solution of baking soda (NaHCO3) in
a 0.500 L volumetric flask, how many grams of baking soda would be needed?
this solution using the materials available to you.
Some salts when dissolved in water make the level of the
solvent decrease when they are added because of the way the particles interact
with each other in solution.You are making
up a 1 molar solution of one of these salts.
If you follow the procedure above, will your solution be
more concentrated than, more dilute than, or exactly 1 molar?Explain why?