Chem#7 - Name Sydney Reid College ID 0591992 Thomas Edison...

Name: Sydney Reid
College ID: 0591992
Thomas Edison State College
General Chemistry I (CHE-111)
Section no.: 7
Semester and year: Oct. 2015
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)
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
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)
1
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