PIEAS Pre Engineering MCQs

Rusting forms new iron oxide substances.
Chemical changes involve rearrangement of atoms and new products.

Density describes how much mass is packed into a volume.
It is commonly expressed in g/cm³ or kg/m³.

The mole is the SI base unit for amount of substance.
One mole contains Avogadro's number of specified entities.

Avogadro's constant gives the number of entities in one mole.
The entities may be atoms, molecules, ions, or formula units.

Molar mass is numerically related to relative atomic or molecular mass.
Its common unit is g/mol.

Average speed uses total path length.
It does not depend on direction.

Average velocity is a vector based on net displacement.
A round trip can have zero average velocity.

Slope gives change in displacement per unit time.
That is the definition of velocity.

Chemistry examines what matter is made of and how it behaves.
It also studies energy changes accompanying chemical processes.

Vectors in the same direction add directly.
The resultant is 12+7 = 19 N.

Opposite collinear vectors subtract in magnitude.
The resultant magnitude is |12-7| = 5 N.

Displacement is a vector from initial to final position.
It can be zero even when distance traveled is not zero.