PIEAS Pre Engineering MCQs

An empirical formula shows the lowest integer ratio of elements.
It may differ from the molecular formula.

A molecular formula is a whole-number multiple of the empirical formula.
It applies to substances composed of discrete molecules.

Balancing follows conservation of atoms and mass.
Coefficients change amounts, not chemical formulas.

Equation coefficients give stoichiometric ratios.
They may be interpreted as molecule or mole ratios.

Matter includes solids, liquids, gases, and plasma.
It is composed of atoms, molecules, or ions.

Once the limiting reactant is used up, no more product can form.
Other reactants may remain in excess.

An element cannot be broken down chemically into simpler substances.
Each element is identified by its atomic number.

Compounds have definite formulas and characteristic properties.
Their components can be separated only by chemical means.

Mixture components retain much of their individual identity.
They can often be separated by physical methods.

Solutions are homogeneous mixtures.
Any sampled portion has approximately the same composition.

Heterogeneous mixtures contain distinguishable regions or phases.
Examples include sand in water and granite.

A physical change alters form or state without changing chemical identity.
Ice and liquid water are both H2O.