If a stock solution of 20.0 g of sugar per 100. ml of solution is available, how much of this stock is needed to prepare 10.0 ml of 5.00 g sugar/ 100. ml solution?

You must use 2.50 mL of the concentrated solution to make 10.0 mL of the dilute solution.

We can use the dilution formula

V_1C_1 = V_2C_2

where

V represents the volumes and

C represents the concentrations

We can rearrange the formula to get

V_2 = V_1 × (C_1/C_2)

V_1 = 10.0 mL; C_1 = 5.00 g/100. mL

V_2 = ?; C_2 = 20.0 g/100. mL

∴ V_2 = 10.0 mL × [(5.00 g/100. mL)/(20.0 g/100. mL)] = 10.0 mL × 0.250

= 2.50 mL

law of conservation of matter

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error