Tltratlon Reactions
1 95
moles of HNO 3 required = /
8 "^
ole
^
H
^
! ) [0 0533 moles Cu(NO,) 2 ]
\3 moles Cu(NOi)2/
= 0 142 moles HNO 3
3 From the number of moles of HNO 3 required, find the volume of HNO 3
solution as specified in the statement of the problem Because the HNO 3 solution
is 6 00 moles/liter, we must use a volume that will provide 0 142 moles That is,
V = 0142 moles HNO. = Q Q ^ ^
6QO moles HN0 3
liter
You will have to add at least 23 7 ml of 6 00 M HNO 3 in order to prepare 10 0 g
of Cu(NO 3 ) 2
TITRATION REACTIONS
Standardization
The concentrations of solutions that are made from concentrated commercial
solutions (such as the H 2 SO 4 solution on p 192) are usually not known very
accurately because the label information may be only approximate, or the
concentrations may change with the opening and closing of the bottles For
example, concentrated HC1 and NH 3 tend to lose their solutes (the odors are
terrible
1 ), NaOH and KOH tend to react with CO 2 from the air, and H 2 SO 4 and
H 3 PO 4 are diluted as they pick up H 2 O from the air As a result, standard
solutions of these compounds can't be made from concentrated commercial
solutions However, it;v possible to make a dilute solution of approximately the
desired concentration (see p 194), and then standardize it by reaction with a
known weight of a pure compound or with a known volume of another standard
solution
The amount of a solution needed to react with a given quantity of another
substance often is determined by a process known as filiation The reagent
solution, the titrant, is added from a buret (a graduated tube) to the sample
solution until chemically equivalent amounts of the two are present The endpoint of the titration corresponds to the use of chemically equivalent amounts,
it often is signaled by a color change in the solution due to the presence of a
suitable indicator The solution in the buret may be a standard solution that is
being used for analysis of the material in the titration flask, or it may be a
solution that is being standardized by reaction with a known amount of material
in the flask In any case, the volume of solution added from the buret to reach
the endpomt is always recorded The two following problems illustrate standardization of solutions by titration *
* In Chapter 20 we present an alternative approach to solving all of the problems in the balance of
this chapter
1 95
moles of HNO 3 required = /
8 "^
ole
^
H
^
! ) [0 0533 moles Cu(NO,) 2 ]
\3 moles Cu(NOi)2/
= 0 142 moles HNO 3
3 From the number of moles of HNO 3 required, find the volume of HNO 3
solution as specified in the statement of the problem Because the HNO 3 solution
is 6 00 moles/liter, we must use a volume that will provide 0 142 moles That is,
V = 0142 moles HNO. = Q Q ^ ^
6QO moles HN0 3
liter
You will have to add at least 23 7 ml of 6 00 M HNO 3 in order to prepare 10 0 g
of Cu(NO 3 ) 2
TITRATION REACTIONS
Standardization
The concentrations of solutions that are made from concentrated commercial
solutions (such as the H 2 SO 4 solution on p 192) are usually not known very
accurately because the label information may be only approximate, or the
concentrations may change with the opening and closing of the bottles For
example, concentrated HC1 and NH 3 tend to lose their solutes (the odors are
terrible
1 ), NaOH and KOH tend to react with CO 2 from the air, and H 2 SO 4 and
H 3 PO 4 are diluted as they pick up H 2 O from the air As a result, standard
solutions of these compounds can't be made from concentrated commercial
solutions However, it;v possible to make a dilute solution of approximately the
desired concentration (see p 194), and then standardize it by reaction with a
known weight of a pure compound or with a known volume of another standard
solution
The amount of a solution needed to react with a given quantity of another
substance often is determined by a process known as filiation The reagent
solution, the titrant, is added from a buret (a graduated tube) to the sample
solution until chemically equivalent amounts of the two are present The endpoint of the titration corresponds to the use of chemically equivalent amounts,
it often is signaled by a color change in the solution due to the presence of a
suitable indicator The solution in the buret may be a standard solution that is
being used for analysis of the material in the titration flask, or it may be a
solution that is being standardized by reaction with a known amount of material
in the flask In any case, the volume of solution added from the buret to reach
the endpomt is always recorded The two following problems illustrate standardization of solutions by titration *
* In Chapter 20 we present an alternative approach to solving all of the problems in the balance of
this chapter