What is the most reliable measurement for the quantity of matter? volume density mass weight

Answer is: mass.

Mass is a fundamental measure of the amount of matter in the object.  Kilogram (symbol: kg) is the base unit of mass in the International System of Units.  

The weight is the force of gravity on the matter.  It is affected by gravity.

Volume is the amount of space that a substance occupies.  It is affected by temperature.

Density is a measure of mass per unit of volume (for example grams per milliliter). It is affected by temperature.

- aluminum and copper chloride.

- the chloride ion to separate the aluminum from the oxygen so that the aluminum can react with the copper ions (and the water molecules).