# Gravimetric analysis ```LECTURE 6: CONCENTRATION- REVIEW
Concentration
• Molality
Review
Molality
Molality (symbolized by m) is the number of moles
of solute per kilogram of solvent.
Molality is used in thermodynamic calculations where a
temperature independent unit of concentration is needed
Calculate the molality of HCl in a solution of hydrochloric
acid in water, containing 30% HCl by weight
The mole fraction of glucose in aqeous solution is 0.2,
then molality of solution is?
A solution of sodium carbonate is prepared by dissolving
0.212g of Na2CO3 and diluting to 100ml. Calculate the
normality of the solution
a. If it is used as a monoacidic base
b. If it is used as a diacidic base
I2 is an oxidizing agent that in reactions with
reducing agents is reduced to iodide ion (I-).
How many grams of I2 would you weigh out to make
0.100 N I2 solution.
Commercially available concentrated hydrochloric acid is
37.0% w/w HCl. Its density is 1.18 g/mL. Using this
information calculate
(a) the molarity of concentrated HCl,
(b) the mass and volume (in milliliters) of solution
containing 0.315 mol of HCl.
The density of concentrated ammonia, which is 28.0%
w/w NH3, is 0.899 g/mL. What volume of this reagent
should be diluted to 1.0 &times; 103 mL to make a solution that
is 0.036 M in NH3?
NEXT LECTURE
```