Question

31. When 9.42 g of methane (CH4) is burned in a bomb calorimeter (heat capacity =

2.677 × 103 J/°C), the temperature rises from 24.00 to 27.08°C. How much heat is absorbed by the calorimeter?

CH4(g) + 2O2(g) → CO2(g) + 2H2O(l); ΔH° = –1283.8 kJ a. 745 kJ

b. 4.84 × 103 kJ c. 8.24 kJ
d. 753 kJ

e. 1.28 × 103 kJ

32. Which of the following statements is incorrect concerning the wave function?

The wave function of a particle is a solution to the Schrödinger equation.

For an electron in an atom, the square of the wave function decreases rapidly as the distance from the nucleus increases.

The square of the wave function is proportional to the probability of finding the particle in a region of space.

The value of the wave function gives the location of the particle.

The wave function for an electron in an atom is called an atomic orbital.

33. What is the wavelength of an electron traveling at of 3.74% the speed of light? (me=9.109×10-31 kg,c=3.00×108m/s,h=6.63×10-34J·s)

a. 1.54×1010 m b. 2.43×10–12 m c. 6.49×10–11 m d. 1.54×1012 m e. 6.49×10–13 m

34. Consider the following energy-level diagram for a particular electron in an atom.

Based on this diagram, which of the following statements is incorrect?
a. The wavelength of a photon emitted by the electron jumping from level 2 to level 1 is

given by .

If the electron is in level 1, it may jump to level 2 by absorbing a photon with energy of ΔE.

If the electron is in level 1, it may jump to level 2 by absorbing any photon having energy of at least ΔE.

We would observe an electron jumping from level 2 to level 1 as a single line in a line spectrum.

If the electron is in level 2, it may jump to level 1 by emitting a photon with energy of |ΔE|.

35. The electron in a hydrogen atom, originally in level n = 8, undergoes a transition to a lower level by emitting a photon of wavelength 3745 nm. What is the final level of the electron?

(c=3.00×108 m/s, h=6.63×10-34 J·s, RH=2.179×10-18 J) a. 5

b. 6 c. 8 d. 9 e. 1

36. When an electron in an atom makes a transition from n = 4 to n = 5, which of the following statements is/are correct?

Energy is emitted.

Energy is absorbed.

The electron loses energy.

The electron gains energy.

The electron cannot make this transition.

a. II and IV b. II and III c. I and IV d. I and III e. V

37. What is the energy per mole of photons with a wavelength of 307.1 nm? (c=3.00×108 m/s,h=6.63×10-34J·s,NA=6.02×1023mol-1)

a. 6.48×10–19 kJ/mol b. 1.85×1014 kJ/mol c. 5.88×1035 kJ/mol d. 9.77×1014 kJ/mol e. 3.9×102 kJ/mol

38. Rank the following ions in order of increasing first ionization energy: O2–, Mg2+, F–, Na+. 9

a. Mg2+ < Na+ < F– < O2– b.Mg2+ <O2– <Na+ <F– c. O2– <F– <Mg2+ <Na+ d.O2– <F– <Na+ <Mg2+ e. O2– <Mg2+ <F– <Na+

39. Below are data on the first four ionization energies for a fictitious element X. First ionization energy = 500 kJ/mol
Second ionization energy = 2000 kJ/mol
Third ionization energy = 3500 kJ/mol

Fourth ionization energy = 25000 kJ/mol
From the data, which of the following statements is incorrect?

The third ionization energy is greater than the second ionization energy because X2+ has a bigger charge than X+.

X could belong to Group IIIA.

X could belong to Group IIIB.

X could belong to group VA.

The fourth ionization energy is much greater than the third ionization energy because

X3+ consists of a noble-gas core or a pseudo-noble-gas core.

40. Using bond-energy data, what is ΔH° for the following reaction?

CH3OH(g) + H2S(g) → CH3SH(g) + H2O(g) Bond Bond Energy (kJ/mol)

C-H 413

C-O 358

O-H 463

C-S 259

S-H 339

a. –25 kJ b. –124 kJ c. 25 kJ
d. –2763 kJ e. 2738 kJ

Answer 1

(31) T2 = 27.08 oC

T1 = 24.00 0C

C = 2.677 X 103 J/oC

q = C delta T

q = 2.677 X 103 J/oC( 27.08-24.00)oC

q = 8.24 KJ

Hence the correct option is c.

(32) the incorrect option is the value of wavefunction gives the location of the particle as square of wavefunction is proportional to the probability of finding the electron in a region of space.

hence incorrect option is the value of wavefunction gives the location of the particle.

(33) 3.74% of speed of light(v) = (3.74X3X108)/100 = 11.22 X 106 m/s

according to De-broglie equation

wavelength = h/mv

wavelength =6.63 X10-34 Js / (9.109X10-31 KgX11.22 X 106 m/s)

wavelength = 6.49 X 10 -11 m

hence the correct option is c.

(34) from all of the options the incorrect option is c as an electron can jump from level one to level 2 with the photon having energy of delta E.

hence the incorrect option is c,i.e.if the electron is in level 1, it may jump tp level 2 by absorbing any photon having energy of atleast delta E.

(35) delta E = hc/lemda

delta E = hc/lemda

delta E = (3.00×108 m/s X6.63×10-34 J·s)/3745 X10-9 m

delta E = 0.00531 X 10-17 J

according to rydberg formula

0.00531 X 10-17 J= 2.179×10-18 J[(1/nf2)-1/82)]

nf = 5

hence the correct option is a.

(36) when an electron goes from lower level to higher lever energy is absorbed by the electron.

hence the correct options are : energy is absorbed and electron gains energy.

correct option is c.

(37)E = hc/lemda

E = (3.00×108 m/s X6.63×10-34 J·s)/307.1 X10-9 m

E = 0.0648 X10-17 J

energy for one mole of photon = 0.0648 X10-17 JX6.02×1023mol-1

energy for one mole of photon = 3.9 X102 KJmol-1

Hence the correct option is e.

(38) order of increasing first ionization energy: O2– < F– < Na+ < Mg2+

higher the size, less the ionization energy as more easy to remove electron.

hence the correct option is d.

(39)

X could belong to Group IIIA.

X could belong to Group IIIB.

X could belong to group VA.

these are incorrect as it belong to group VIII.

(40)ΔH° = (3CH +CH +SH 2OH) - (3CH+CO+OH+2SH)

Hence putting all the value the ans is -25 KJ.

hence the correct option is a.