WA 07_CHE-121-jan18.docx - Name John Hendrie College ID...

Name: John Hendrie
College ID: 0571667
Thomas Edison State University
General Chemistry I with Labs (CHE-121)
Section no.: 010
Semester and year:Jan2018
Written Assignment 7: Energy and Thermochemistry
Answer all assigned questions and problems, and show all work.
1. Consider this reaction:
2CH
3
OH( l ) + 3O
2
( g ) → 4H
2
O( l ) + 2CO
2
( g ) ∆ H = –1452.8 kJ/mol
a. Is this reaction endothermic or exothermic? (2 points)
b. What is the value of ∆ H if the equation is multiplied throughout by 2?
points)
(2
c. What is the value of ∆ H if the direction of the reaction is reversed so that
the products become the reactants and vice versa? (2 points)
d. What is the value of ∆ H if water vapor instead of liquid water is
formed as the product? (2 points)
2. The first step in the industrial recovery of zinc from the zinc sulfide ore is
roasting, that is, the conversion of ZnS to ZnO by heating:
2ZnS( s ) + 3O
2
( g ) → 3ZnO( s ) + 2SO
2
( g ) ∆ H = –879 kJ/mol
Calculate the heat evolved (in kJ) per gram of ZnS roasted. (5 points)