Physical Chemistry Answers

Which of the following statements explains why silicon dioxide has a high melting point?

A. It has a giant ionic structure with strong electrostatic attraction between ions.

B. It has a giant covalent structure with strong covalent bonds between atoms.

C. It has a simple molecular structure with weak forces between molecules.

D. It has a giant metallic structure with a strong attraction between positive ions and the sea of electrons

The electron-dot structure (Lewis structure) for which of the following molecules would have two unshared pairs of electrons on the central atom?

A. H₂S

B. NH₃

C. HCN

D. CH₄

E. CO₂

CCl₄, CO₂, PCl_3, PCl₅, SF₆, . Which of the following does not describe any of the molecules above?

A. Linear

B. Octahedral

C. Tetrahedral

D. Trigonal Planar

The structural isomers C₂H₅OH and CH₃OCH₃ would be expected to have the same values for which of the following? (Assume ideal behavior)

A. Gaseous densities at the same temperature and pressure

B. Vapour pressures at the same temperature

C. Boiling points

D. None of the above

THe liquefied hydrogen halides have the normal boiling points. The relatively high boiling point of HF can be correctly explained by which of the following?

A. HF gas is more ideal

B. HF molecules have smaller dipole moment

C. HF is the strongest acid

D. HF molecules tend to form hydrogen bonds

In which compound are there Pi-bonds?

A. C₃H₈

B. C₃H₄

C. C₂H₄

D.KCl

₉₄²⁴¹Pu successively emits, β, α, α, β, α, α, particles. At that point, the nuclide becomes:?

A. ₉₄²²⁵Ra

B. ₈₈²²⁵Ra

C. ₈₄²⁰⁷Ra

D. ₈₄²¹⁹Pu

A certain natural decay series stars with ₉₂²³⁸U and ends with ₈₂²⁰⁴Pb. Each step involves the loss of either an α-particle or a β-particle. What is the number of α-particles released?

What is the number of β-particles released?

How did we attain the second electron of affinity