PIEAS Chemistry MCQs

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.

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.

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

An excess reactant is supplied beyond the stoichiometric requirement.
Some remains when the reaction is complete.

Theoretical yield assumes complete reaction and no losses.
It is calculated from the limiting reactant.

Actual yield is measured after the experiment.
It is usually lower than theoretical yield.

Percent yield measures reaction and recovery efficiency.
Values below 100% commonly result from losses or incomplete reaction.

Molarity is a common concentration unit.
Its value changes with temperature because solution volume can change.

Molality is based on solvent mass.
It is largely independent of temperature.