Chemistry Reference
In-Depth Information
Practice Problem 10.24
What mass of
Na
2
SO
4
(aq)
will result from
the reaction of 22.7 g of NaOH(aq) and 10.0 g of H
2
SO
4
(aq)?
EXAMPLE 10.25
Calculate the quantity of
H
2
O
present after the reaction of 0.425 mol HCl and
0.100 mol
Al(OH)
3
(s)
in 12.00 mol of water.
Solution
Step 1:
3 HCl(aq)
Al(OH)
3
(s) £ AlCl
3
(aq)
3 H
2
O(
/
)
Step 2:
Present initially
0.425
mol
HCl
3
mol
HCl
0.425 mol
0.100 mol
0.00 mol
12.00 mol
0.1417
Steps 3 and 4:
Change due
to reaction
0.100
mol
Al
1
mol
Al
0.100
0.100 mol
0.300 mol
0.300 mol
0.100 mol
Al is limiting.
Step 5:
Present finally
0.125 mol
0.000 mol
0.100 mol
12.30 mol
The fact that some water was present initially does not affect the solution
method.
Practice Problem 10.25
Calculate the number of moles of sodium
acetate present after a solution containing 0.400 mol of acetic acid,
and 0.100 mol of sodium acetate,
HC
2
H
3
O
2
,
NaC
2
H
3
O
2
,
in 10.00 mol of water, is treated
with 0.300 mol of NaOH.
Snapshot Review
❒
When a reaction of two or more substances has proceeded until one
of the reactants has been used up, the reaction stops. To determine
which reactant is limiting, divide the number of moles of each by its
coefficient in the balanced equation. The lowest quotient is that of the
limiting quantity. Do not use these quotients for any further
calculations.
ChemSkill Builder 4.4
A. For each part determine which reactant in the following equation is
limiting:
2 Ag(s)
S(s) £ Ag
2
S(s)
(a) 2 mol Ag and 1.5 mol S
(b) 4 mol Ag and 1 mol S
(c) 2 mol Ag and 2 mol S
B. (a) How much Ag would react with 2.5 mol S?
(b) How much S would react with 4.0 mol Ag?
(c) How much Ag and how much S react when 2.5 mol S and 4.0 mol
Ag are heated together?
