ECAT Chemistry MCQs

The ideal gas equation combines several gas laws.
It relates pressure, volume, amount, and absolute temperature.

Use V1/T1=V2/T2.
V2=2.0×450/300 = 3.0 L.

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.

Dalton's law treats each ideal gas independently.
Total pressure is the sum of partial pressures.

Use n=PV/RT.
N=100×24.6/(8.31×300)≈0.987 mol.

Particles move from regions of higher concentration toward lower concentration.
Diffusion occurs in gases, liquids, and solids.

Dalton's law adds partial pressures.
20+35+45 = 100 kPa.

Effusion rates depend on molar mass.
Lighter gases generally effuse faster.

Moles equal molarity times volume in liters.
0.50×2.0 = 1.0 mol.

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.