Deck 3: Introduction to Quantum Mechanics and Chemical Bonding

Question 1

The position of an electron in a Be²⁺ ion is known to 5.0´10^-11 m. What is the uncertainty in its velocity?

A) 2.0´10⁵ m s^-1
B) 1.2´10⁶ m s^-1
C) 4.6´10⁶ m s^-1
D) 9.2´10⁶ m s^-1
E) 3.0´10⁸ m s^-1

Answer 1

1.2´10⁶ m s^-1

Question 2

If the bond in carbon monoxide is modeled as a harmonic oscillator the force constant is 1860 N m^-1, and the reduced mass is 6.86 amu. What is the energy of the ground vibrational state of CO?

A) 1.35´10^-21 J
B) 2.71´10^-21 J
C) 3.53´10^-21 J
D) 2.13´10^-20 J
E) 4.26´10^-20 J

Answer 2

2.13´10^-20 J

Question 3

The work function for aluminum is 6.53´10^-19 J. If a surface of aluminum is irradiated with 400 nm what is the maximum kinetic energy of the electrons emitted from the surface due to the photo-electric effect?

A) 4.13´10⁵ m s^-1
B) 5.85´10⁵ m s^-1
C) 1.04´10⁶ m s^-1
D) 1.20´10⁶ m s^-1
E) no electrons will be emitted

Answer 3

no electrons will be emitted

Question 4

Proper wavefunctions ( ) in quantum mechanics must be normalized. Which statement below best summarizes this mathematically?

A)

B)

C)

D)

E)

Question 5

Before the discovery of the element germanium in 1886, its existence was predicted by Mendeleev as "eka-silicon". Mendeleev not only predicted the existence of this element but also its properties. Use the density of the neighboring elements to estimate the density of Ge.

A) 2.5 g cm^-3
B) 4 g cm^-3
C) 5.5 g cm^-3
D) 7 g cm^-3
E) 9.6 g cm^-3

Question 6

Given the following the data, what is the energy change for this reaction? Na(g) + Cl(g) $\rightarrow$ Na⁺(g) + Cl^-(g)

A) -1198.4 kJ mol^-1
B) -146.8 kJ mol^-1
C) +146.8 kJ mol^-1
D) +672.6 kJ mol^-1
E) +1198.4 kJ mol^-1

Question 7

Which of the following is the best Lewis diagram for formaldehyde, CH₂O?

A)

B)

C)

D)

E)