Enthalpy Of Reaction And Calorimetry Worksheet Page 12
ADVERTISEMENT
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20SUPPLEMENTARY ENTHALPY PROBLEMS
1.
Construct an enthalpy diagram showing the enthalpy changes for a one step conversion of germanium,
Ge (s) , into GeO 2 (s) and a two step conversion - first to the monoxide, GeO (s) followed by the
oxidation to GeO 2 (s) . The relevant thermochemical equations are as follows;
→
∆H° = -255 kJ
Ge (s)
+
1/2 O 2 (g)
GeO (s)
→
∆H° = -534.7 kJ
Ge (s)
+
O 2(g)
GeO 2 (s)
Using this diagram, determine the value of ∆H° for the reaction
→
GeO (s)
+
1/2 O 2 (g)
GeO 2 (s)
Ge + O 2
0
GeO
PE
-255
(kJ)
GeO 2
-534.7
2.
Nitrogen monoxide oxidizes to the toxic red brown gas nitrogen dioxide in air. Construct an accurate
enthalpy diagram for this reaction. Use the diagram to explain which of the oxides of nitrogen has
stronger covalent bonds.
→
2 NO (g)
+
O 2 (g)
2 NO 2 (g)
One of the “building blocks” for proteins such as those in muscles and in sinews, is an amino acid called
3.
glycine, C 2 H 5 NO 2 . The equation for its combustion is
→
4 C 2 H 5 NO 2 (s)
+
9 O 2 (g)
8 CO 2 (g) +
10 H 2 O (l)
+
2 N 2 (g)
The value of its ∆H comb is -973.49 kJ/mol. Calculate ∆H f for glycine.
4.
On Easter Sunday, April 3, 1983, nitric acid spilled from a tank car near Denver, Colorado. The spill
was neutralized with sodium carbonate. The reaction is
→
2 HNO 3 (aq)
+
Na 2 CO 3 (s)
2 NaNO 3 (aq)
+
H 2 O (l)
+
CO 2 (g)
(a) Calculate ∆H° for this reaction. ∆H f for NaNO 3 (aq) is -467 kJ/mol, ∆H f for HNO 3 (aq) is -
207.16 kJ/mol, ∆H f for Na 2 CO 3 (aq) is -1129.60 kJ/mol]
(b) Approximately 9.1 x 10 4 L of nitric acid was spilled. Assuming a molar concentration of 15.4M,
how much sodium carbonate was required for complete neutralization and how much heat was
evolved.
(c) According to the Denver Post for April 4, 1983, authorities feared a volatile reaction might occur
during the neutralization. Considering the magnitude of ∆H°, what was their major concern?
(d) Predict the sign of ∆Srxn and ∆Grxn.
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Education