1) we find out the volume of the water.
Remember: 1 ml=1 cm³
Volume of the water=number of cups x volume of one cup.
Volume of the water=2.5(240 ml)=600 ml=600 cm³
Density=mass/volume ⇒ mass=density x volume
2) we calculate the water mass of 600 cm³ of water.
mass=density x volume
mass=(1 g/cm³)(600 cm³)=600 g.
Answer: the mass of 2.5 cupas of water is 600 g.