the density of water 20 degrees celcius is 1.00g?mL and the densityof ethylene glycol is 1.114g/mL, if 100.0mL if water is combined with 25.0mL is ethylene glycol, what would be the density of this mixture?

Answer 1

I wonder if your prof expects us to assume the volumes are additive? If so here is what you do.
100 mL H2O x 1.00 g/mL = 100 grams.
25.00 mL ethylene glycol x 1.114 g/mL = 27.85 grams.
Total mass = 127.85 g
Total volume, if they are additive, is 125 mL.
Density = mass/volume = ?