1) We started off the day by checking in the molarity packet
and worksheets with Mrs. Friedmann.
2) Later we checked the homework and asked questions. The
key is posted on Moodle.
Class Notes:
Big Ideas About
Molarity:
(Also posted on Moodle)
1) Molarity is MOLES solute and LITERS solution.
(Not liters water)
2) If you are given grams solute then convert to moles. If you are given mL solution then convert to
liters
3) What if you are given GRAMS of solution? How do you
convert to volume of solution? You would need density of
solution.
Example:
g solution x mL solution/ g solution x 1 L solution/ 1000mL
solution = L solution!
4) You should know how to mix up a solution of a particular
molarity, at a specific volume.
How to Mix a
Solution:
(Also posted on Moodle)
Suppose you work in a chemistry lab. Your boss tells you to
make 0.50 liters of a 0.75 M solution of sodium chloride. How would you do it?
Calculations:
0.75 mols NaCl/ 1 L solution x 0.50 L solution = 0.38 mols
NaCl needed
Procedure:
1) Measure 22g of NaCl, using a balance.
2) Put the NaCl into a 500 mL volumetric flask with less
than 500mL water in it.
3) Swirl until all the NaCl is completely dissolved.
4) Fill the volumetric flask to the 500mL mark.
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