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CHM/150 Week 4 Hess' Law Name:-(Answered)


Step-by-step Instant Solution


All the questions and instructions are attached. Please help thank you.



Week 4 Hess? Law


Name: _____________________________________________________



University of Phoenix Material


Instructions: Highlight the entire most correct answer for each problem or answer the


questions or fill in the blanks ? must show work for full credit in calculation problems.


Review the following Youtube video:


1. Calculate the standard enthalpy change, ?Ho, for the formation of 1 mol of strontium


carbonate (the material that gives the red color in fireworks) from its elements.


Sr (s) C(graphite)








O2 (g)



SrCO3 (s)



The information available is





Sr (s)








O2 (g) SrO (s)



(2) SrO (s) CO2 (g) SrCO3 (s)


(3) C(graphite) O2 (g) CO2 (g)



H - 592 kJ


H - 234 kJ


H - 394 kJ



2. The combination of coke and steam produces a mixture called coal gas, which can be


used as a fuel or as a starting material for other reactions. If we assume coke can be


represented by graphite, the equation for the production of coal gas is


2 C (s) 2 H2O (g) CH4 (g) CO2(g)


Determine the standard enthalpy change for this reaction from the following


standard enthalpies of reaction :


(1) C(s) H2O (g) CO (g) H2 (g)


(2) CO (g) H2O (g) CO2 (g) H2 (g)



H 131.3 kJ


H - 41.2 kJ



(3) CH4 (g) H2O (g)



H 206.1 kJ



3 H2 (g) CO (g)



3. The enthalpy change due to a temperature change is a change in





Week 4 Hess? Law


Name: _____________________________________________________


A. kinetic energy.


B. potential energy.


4. An enthalpy change at constant temperature and pressure is


designated by the symbol


A. q


B. H


C. _H


D. c


5. The molar enthalpy change for a process is designated by the




A. q


B. H


C. H


D. c


6. Another word for melting is _______________.


7. Another word for boiling is _______________.


8. Calculate the enthalpy change when a 10.0 g of water is heated


from 10.0?C to 25.0?C.


Show working.



9. Calculate the enthalpy change when 10.0 g of water at 100?C is


converted to 10.0 g of


Vapor at 100?C. Show work.



10. Calculate the total change in enthalpy when 100 g of ice at -5.00?C


is converted to water at 85.00?C. Show work.




Paper#9256653 | Written in 27-Jul-2016

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