CHEM 30 HOMEWORK HELP (+ EXPLANATION)

Use the following information to answer the next question.
                   
                      1.  Methane
                      2.  Ethene
                      3.  Butane
                      4.  Methanol

12) The order of the compounds shown above when they are listed from least thermally stable to most thermally stable is

A) 1, 2, 4, 3
B) 2, 1, 3, 4 
C) 3, 4, 2, 1
D) 4, 3, 1, 2 

13) Based on the enthalpy of formation of MgO, the energy required to decompose 48.6 g of MgO is

A) 60.3 kJ 
B) 301 kJ 
C) 603 kJ 
D) 725 kJ 

14) The molar enthalpy of formation of sodium azide is

A) -43.5 kJ/mol 
B) -21.8 kJ/mol 
C) +21.8 kJ/mol 
D) +43.5 kJ/mol 

15) The amount of energy involved when 100 g of This is NaN3 decomposes is

A) 43.5 kJ 
B) 1.54 kJ 
C) 33.5 kJ 
D) 66.8 kJ 

Use the following information to answer the next question.

Ammonia is produced by the Haber process.  This process involves injecting hydrogen and nitrogen into a heated reaction vessel.  The overall reaction involved is > N2(g) + 3H2(g) ----> 2NH3(g) + heat

16) The enthalpy of reaction for the production of ammonia shown above is

A) +45.9 kJ 
B) +91.8 kJ 
C) -45.9 kJ 
D) -91.8 kJ 


Use the following information to answer the next question.

Sulfuric acid is used to dissolve copper ore in many mining operations.  Sulfuric acid may be produced on site by burning sulfur and dissolving the products in water.  The overall equation for this reaction is

S8(s) + 12O2(g)+8H20(l) ----> 8H2S04(l) +4225.6 kJ

18) In this process, the enthalpy of reaction for one mole of sulfuric acid is

A) +4225.6 kJ 
B) +528.2 kJ 
C) -528.2 kJ 
D) -4225.6 kJ 

Nitrogen gas, a stable component of air, reacts with oxygen at high temperatures to produce nitrogen oxides.  The balanced reaction for this process is > N2(g) + 2O2(g) ----> 2NO2(g)

19) The description of the reaction above indicates that this reaction

A) is exothermic 
B) is endothermic 
C) is releasing energy 
D) has products that have less energy than do the reactants 


Use the following graph to answer the next question.

THUMBNAIL #1
 

20) deltarH for the combustion reaction shown in the graph above is
 
A) -951.9 kJ 
B) +951.9 kJ 
C) -802.3 kJ 
D) +802.3 kJ 

21) Use information from your Table of Standard Molar Enthalpies of Formation in your Data Booklet to determine which of the following compounds has the strongest intramolecular bonds.

A) HBr (g) 
B) HCl (g) 
C) HF (g) 
D) HI (g) 

Use the following information to answer the next question.  The reaction between phosphoric acid and lithium hydroxide is shown below.

H3PO4(aq) + 3LiOH ---> Li3PO4(aq) + H2O(l) + energy


22) The reaction above can best be described as
 
A) endothermic with a negative enthalpy 
B) exothermic with a negative enthalpy 
C) endothermic with a positive enthalpy 
D) exothermic with a positive enthalpy
 

Use the following information to answer the next question.

THUMBNAIL #2

23) The enthalpy of reaction for (THUMBNAIL #3) is
 
A) -98.9 kJ 
B) +98.9 kJ 
C) -692.5 kJ 
D) +692.5 kJ
 
24) Show and/or explain your work in determining the change in enthalpy for the production of the hot chemical spray described above. THUMBNAIL #4