Answer:
69.66 g
Step-by-step explanation:
We have the following from the question;
Density of the substance = 5.4 g/ml
Volume of substance = 12.9 ml
Mass of substance= the unknown
Since we have both density and volume of the substance, the question must be for us to obtain the mass of the substance, hence;
Density= mass/volume
Mass= Density × volume
Mass = 5.4 g/ml × 12.9 ml
Mass= 69.66 g