MDCAT Chemistry MCQs

Allotropes differ in atomic arrangement and properties.
Diamond and graphite are carbon allotropes.

Graphite has delocalized electrons within its layers.
These electrons allow electrical conduction.

Every carbon is tetrahedrally bonded to four others.
The extended network resists deformation.

Amphoteric oxides can behave as acidic or basic substances.
Aluminum oxide and zinc oxide are examples.

SO3 is a nonmetal oxide and forms sulfuric acid with water.
Metal oxides listed are predominantly basic.

For first order, rate=k[A].
Rate=0.20×0.50=0.10 M/s.

Sodium oxide reacts with water to form sodium hydroxide.
It is a strongly basic metal oxide.

Positive E° corresponds to negative standard Gibbs energy.
The written cell reaction is thermodynamically favorable.

Electrolysis drives oxidation and reduction at electrodes.
It is used in plating, refining, and chemical production.

PH=-log(1×10^-3).
The result is 3.

POH=-log(1×10^-4).
The result is 4.

At 25°C, pH+pOH=14.
POH=14-5 = 9.