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Physical Chemistry
b) Using Balmer series, calculate ionisation energy of hydrogen atom in kJ mol1.
Physical Chemistry
a) Using Bohr atomic model, drive expression for calculating the radius of orbits
in He+. Using this expression, calculate the radius of fourth orbit of He+ ion.
in He+. Using this expression, calculate the radius of fourth orbit of He+ ion.
Physical Chemistry
A 3.25 gram sample of solid calcium carbide (CaC2) reacts with water to produce acetylene gas (C2H2) and aqueous calcium hydroxide. If the acetylene was collected over water at 17oC and 740.0 mmHg, how many milliliters of acetylene were produced?
Physical Chemistry
In a fuel cell methanol is used as fuel and oxygen gas is used as an oxidizer. The reaction is
CH3OH(l) + O2(g) → CO2(g) + 2H2O(l)
At 298 K standard Gibb's energies of formation for CH3OH(l), H2O(l) and CO2(g) are –166.2, –237.2 and –394.4 kJ mol–1 respectively. If standard enthalpy of combustion of methanol is –726 kJ mol–1, efficiency of the fuel cell will be
CH3OH(l) + O2(g) → CO2(g) + 2H2O(l)
At 298 K standard Gibb's energies of formation for CH3OH(l), H2O(l) and CO2(g) are –166.2, –237.2 and –394.4 kJ mol–1 respectively. If standard enthalpy of combustion of methanol is –726 kJ mol–1, efficiency of the fuel cell will be
Physical Chemistry
On the basis of the following thermochemical data:
(ΔfG°H+(aq) = 0)
H2O(l) → H+ (aq) + OH− (aq); ΔH = 57.32 kJ
H2 (g) + O2(g) → H2O(l) ΔH = −286.20kJ
The value of enthalpy of formation of OH− ion at 25°C is
(ΔfG°H+(aq) = 0)
H2O(l) → H+ (aq) + OH− (aq); ΔH = 57.32 kJ
H2 (g) + O2(g) → H2O(l) ΔH = −286.20kJ
The value of enthalpy of formation of OH− ion at 25°C is
Physical Chemistry
The Gibbs energy for the decomposition Al2O3 at 500°C is as follows:
Al2O3 → Al + O2, ΔrG = +966kJ mol–1
The potential difference needed for electrolytic reduction of Al2O3 at 500°C is at least
Al2O3 → Al + O2, ΔrG = +966kJ mol–1
The potential difference needed for electrolytic reduction of Al2O3 at 500°C is at least
Physical Chemistry
Relationships between Kp,Kc and Kx for reactions involving ideal gases
Physical Chemistry
Question 19 : Which of the following statements about the kinetics of the reaction
H
2
(
g
)
+
B
r
2
(
g
)
→
2
H
B
r
(
g
)
H2(g)+Br2(g)→2HBr(g)
is definitely true?
The presence of hydrogen bromide, HBr, inhibits the rate of the reaction
The reaction is first order with respect to bromine, Br2.
It is not possible to determine anything about the kinetics of the reaction from the stoichiometry.
The reaction is second order overall.
Question 20 : Rate of reaction is defined as the
None of the above
Rate of change of conc. of product only
Rate of change of conc. of reactant only
Rate of change of concentration Of either reactant or product per unit time
H
2
(
g
)
+
B
r
2
(
g
)
→
2
H
B
r
(
g
)
H2(g)+Br2(g)→2HBr(g)
is definitely true?
The presence of hydrogen bromide, HBr, inhibits the rate of the reaction
The reaction is first order with respect to bromine, Br2.
It is not possible to determine anything about the kinetics of the reaction from the stoichiometry.
The reaction is second order overall.
Question 20 : Rate of reaction is defined as the
None of the above
Rate of change of conc. of product only
Rate of change of conc. of reactant only
Rate of change of concentration Of either reactant or product per unit time
Physical Chemistry
Question 16 : A beaker with a mixture of ice and water is maintained at equilibrium:
H
2
O
(
s
)
+
h
e
a
t
→
H
2
O
(
l
)
H2O(s)+heat→H2O(l)
; If the temperature of the system is decreased:
No change occurs
The container cacks
Ice melts to form liquid water (shift to the right)
Water freezes to form ice (shifts to the left)
Question 17 : The term — dx/dt in the rate expression refers to the
Average rate of the reaction
increase in concentration of the reactants
instantaneous rate of the reaction
Change in concentration of the reactants with time
Question 18 : Rusting of iron Is an example of________ reaction
Fast
Slow
explosive
Moderate
H
2
O
(
s
)
+
h
e
a
t
→
H
2
O
(
l
)
H2O(s)+heat→H2O(l)
; If the temperature of the system is decreased:
No change occurs
The container cacks
Ice melts to form liquid water (shift to the right)
Water freezes to form ice (shifts to the left)
Question 17 : The term — dx/dt in the rate expression refers to the
Average rate of the reaction
increase in concentration of the reactants
instantaneous rate of the reaction
Change in concentration of the reactants with time
Question 18 : Rusting of iron Is an example of________ reaction
Fast
Slow
explosive
Moderate
Physical Chemistry
Question 13 : The minimum additional energy, above the average internal energy, which the reacting molecules must possess so that their collision result in a reaction is known as
Thermodynamic energy
Activation energy
Kinetic energy
Threshold energy
Question 14 : The factor that affects the rate of reaction is
Catalyst
All of these
Temperature of the reactants
Nature and concentration of the reactants
Question 15 : In a reaction:
2
A
→
B
+
2
C
2A→B+2C
, which of the statement is true?
Rate of formation of B = Rate of disappearance of A
Rate of disappearance of A = Rate of formation of C
Rate of disappearance of A = Rate of formation of B
Rate of formation of C= Rate of formation of B
Thermodynamic energy
Activation energy
Kinetic energy
Threshold energy
Question 14 : The factor that affects the rate of reaction is
Catalyst
All of these
Temperature of the reactants
Nature and concentration of the reactants
Question 15 : In a reaction:
2
A
→
B
+
2
C
2A→B+2C
, which of the statement is true?
Rate of formation of B = Rate of disappearance of A
Rate of disappearance of A = Rate of formation of C
Rate of disappearance of A = Rate of formation of B
Rate of formation of C= Rate of formation of B
