You would know that the variable is quantitative if it shows any number to express the quantity. For example, quantitative variables are 50°C, 5 atm, 2 moles, 100 L and so on. A variable is qualitative if it expresses a relative quantity but not expressing a number. Examples would be: few, too hot, several, or even describing the characteristics of a variable. Hence, when the variable is in grams, then that would be quantitative.
