ECAT MCQs

Low pressure keeps particles far apart.
High temperature reduces the relative importance of attractions.

Use P1/T1=P2/T2.
P2=100×600/300 = 200 kPa.

Solid particles occupy fixed average positions.
They still vibrate about those positions.

Carbon has two electron domains from the two double bonds.
They arrange 180 degrees apart.

A liquid takes the shape of its container.
Its particles remain close but can flow past one another.

Boron has three bonding regions and no lone pairs.
The molecule is planar with approximately 120-degree angles.

A gas expands to fill its container.
Its particles are widely separated and move rapidly.

Four equivalent bonding directions correspond to sp3 hybridization.
The ideal geometry is tetrahedral.

Sublimation bypasses the liquid phase.
Dry ice changing to carbon dioxide gas is an example.

Each carbon has three sigma-bonding regions.
The remaining p orbitals form the pi bond.

Deposition is the reverse of sublimation.
Frost formation is a familiar example.

Each carbon has two electron domains.
Sp hybridization gives linear geometry and leaves two p orbitals for pi bonds.