The mass is expressed in grams (g). Mass is an extensive property of a substance. Extensive properties depend on the quantity of the substance. Volume, usually measured in units of milliliters (mL), liters (L), or cubic centimeters (cm 3) is also an extensive property. Volume is a measure of the amount of space a substance occupies. If the substance is in a liquid or gaseous state, its occupied space or volume is measured in liters (L) or milliliters (mL). When a substance is a liquid, its volume can be measured directly in a graduated cylinder, which is a piece of calibrated glassware.