1.
a)
b)
c)
d)
All of ∆Ho given below are heats of formation except:
C(s) +2H2(g) → CH4(g)
2 H2 (g) + O2(g) → 2H2O(g)
½ N2 (g) + 3/2 H2(g) → NH3(g0
½ H2(g) + ½ Cl2 (g) → HCl(g)
2.
Given ∆Hof [CO2 =-394, H2O= -286, C6H12O6= 1260] kj/ mol , The ∆Horec for
the following reaction is
6CO2 (g) + 6H2O(l) → C6H12O6 (s) + 6O2(g)
Calculate the kinetic energy in Joules of 45g golf-ball moving at 61 m/s.
3.
Calculate ∆E, and determine whether the process is endothermic or exothermic
for the following cases?
a) A system absorbs 105Kj of heat from its surroundings, while doing 29kj of work
on the surroundings
b) Q=1.50 kj and w=-657 j
c) The system releases 57.5 kj of heat while doing 22.5 kj of work on the
surrounding
4.
5.
2C(graphite) + 2H2(g) → C2H4 (g) ∆Hof =52.30 kj/ mol
2C(graphite) + 3H2(g) → C2H6 (g) ∆Hof =-84.68 kj/mol
The standard enthalpy change, ∆Ho for the reaction: C2H4 (g) + H2(g) → C2H6 (g) is:
6.
The combustion of glucose is described by: C6H12O6 (s) + 6O2(g) →6CO2 (g) +
6H2O(l),, The mass of glucose in gm that must be burned to produce 47 KJ of
heat is:
7.
What quantity of heat is liberated by combustion of 100gm of N2H4
N2H4 (l) + O2 (g) → N2(g) + 2H2O (l) ∆Ho = -622.4 KJ
8.
Under conditions of constant volume, the heat changes that occurs during a
chemical reaction is equal to:
a) ∆H
b)∆T
c)∆W
d)∆E
9.
A gas expands from 14L to 20L against a constant opposing pressure of 10 atm.
The gas also absorbs heat equal to 20 L atm. For change described, the value of
∆E is equal to:
10.
Given the following reactions and their respective enthalpy changes
C2H2 (g) + 5/2 O2(g) →2CO2 (g) + H2O(l) ∆H=-1299.6 KJ
C(s) + O2(g) → CO2(g)
H2(g) +1/2 O2(g) →H2O(l)
∆H=-393.5KJ
∆H=-285.9KJ
Then ∆H(in KJ) for reaction 2C(s)+ H2(g) → C2H2 (g) is:
11.
For the reaction: 2NH3 (aq) → N2(g) + 3H2(g) ,, ∆H=169.9KJ
will be:
12.
a)
b)
c)
d)
13.
∆Ho of which reaction corresponds to ∆Hf:
Ca(OH)2 (s) → CaO(s) + H2O (l) ∆Ho=15.6 Kcal
4HNO3 (l) → N2O5 (g) + H2O (l) ∆Ho=36.6 Kcal
2C(s) + H2(g) →C2H2 (l)
∆Ho=54.2 Kcal
4C(s) + 2H2 (g) → 2C2H2(l)
∆Ho=108.4 Kcal
What is the amount of heat evolved when 494 g of Fe2O3 is formed [∆Hf for
Fe2O3=-824KJ/mol]
Given the following reactions:
2SO2 (g) + O2 (g) → 2SO3 (g)
∆Ho=196 KJ
2S (s)
+ 3O2 (g) → 2SO3(g) ∆Ho=-790 KJ
Calculate ∆Ho for the reaction: S(s) + O2(g) → SO2(g)
-187 KJ
187 KJ
-297 KJ
303 KJ
14.
a)
b)
c)
d)
15.
a)
b)
c)
d)
One (or more) of the following expressions is (are) correct:
∆E = qp + P∆V (at constant pressure)
∆E = qp - P∆V (if the only work available of expand)
∆E = ∆H+ P∆V
∆E = qp
16.
a)
b)
c)
In which of the following reactions is ∆H not equal to ∆E:
HCl (aq) + NaOH(aq) → NaCl (aq) +H2O (l)
C(s) +O2(g) → CO2(g)
H2(g) + I2(g) →2HI(g)
∆Hf for NH3
d) N2(g) + 3H2(g) → 2NH3(g)
17.
a)
b)
c)
d)
18.
For the reaction: 2NH3 (aq) → N2(g) + 3H2 (g) ∆H=169.9KJ, ∆Hf for NH3
will be:
169 KJ
84.9 KJ
-84.9 KJ
120.8 KJ
In which of the following reactions is ∆H not equal to ∆E?
HCl (aq) +NaOH (aq) →NaCl(aq) + H2O(l)
C(s) + O2 (g) → CO2 (g)
H2(g) + I2(g) →2HI(g)
N2(g) +3H2(g) →2NH3(g)
19.
The specific heat of iron metal is 0.450J/g.k. How many J of heat are necessary to
raise the temperature of a 1.05Kg block of iron 250C to 88.5oC?
20.
From the enthalpies of reaction
2H2(g) + O2(g) → 2H2O(g)
∆H=-483.6KJ
3O2(g) → 2O3(g)
∆H=+284.6KJ
Calculate the heat of the reaction:3H2(g)+O3(g) →3H2O(g)
21. Consider the following reaction: CH3OH(g) →CO2 (g)+ 2H2(g) ∆H=90.7KJ
a) Is heat absorbed or released in the course of this reaction
b) Calculate the amount of heat transferred when 45g of CH3OH is decomposed by
this reaction at constant pressure