Name___________________
Period__________________
Chemistry Quiz
B)
Give the letter that represents the following:
______1) Δ H
______2) kinetics
______3) thermodynamics
______4) enthalpy of reactants
______5) activation energy
______6) enthalpy of the products
C)
A)
(F)
D)
E)
Is this reaction endothermic or exothermic ?_____________________
Is its
H value positive or negative ?______________________
III.Problems: Show work
1) Given, 4NH3
decomposes.
2 N2
+ 6 H2 ,
H = 184 kJ , find the heat absorbed when 82.4 g of NH3
1)
2) 75 ml of substance A reacts with 75 ml of substance B in a coffee cup calorimeter. The temperature of the
reactants start at 22.9 C and peak at 15.7 C after the reaction. A) How much heat was absorbed by the reaction
assuming the mixture has a density of 1 g/ml and the specific heat is 4.18 J / g C ? B) Assuming that 1 mol of A
reacted with 1 mol of B to form AB, write a thermochemical equation for the reaction.
2a)
2b)
3) Find the heat of reaction for 2 B(s) + 3 H2(g)
Given
B2H6(g) + 3 O2 (g)
2 B(s) + 3/2 O2 (g)
H2(g) + 1/2 O2 (g)
H2O(l)
H2O(g)
B2H6(g)
B2O3 (s) + 3 H2O(l)
B2O3 (s)
H2O(g)
ΔH
-2035 KJ
-1273 KJ
-286 KJ
44 KJ
`
3)
4) Use your thermodynamic tables to find Δ H , Δ G, and Δ S for the following reaction;
4 NH3 + 5 O2
4 NO + 6 H2O (all gases)
ΔH
ΔS
ΔG
Spontaneous? ____________
5) Find
use table.
G @ 298 K for 4Fe + 3O2(g)
2Fe2O3(s) if Δ H is –1652 kJ and Δ S is –543 J/K. do not
5)
Is this reaction spontaneous?
6) Predict the sign of Δ S for the following reactions. Negative or positive change?
______
______
______
______
.
N2(g) + 3 H2 (g)
3 O2(g)
H2(g)
2 N2(g) + O2(g)
2 NH3(g)
2 O3(g)
2 H(g)
2N2O (g)