The relation between density and mass and volume is
[tex]Density=\frac{Mass}{volume}[/tex]
the dose required is 2.5 tsp
each tsp contain 5mL
So dose required in mL = 2.5 X 5 = 12.5 mL
the mass will be calculated using following formula
[tex]Mass=DensityXvolume[/tex]
[tex]Mass=1.23\frac{g}{mL}X12.5mL= 15.38g[/tex]
The mass of dose in grams will be 15.38 g