Question

Determine the new concentration, in mg/mL, of the starch solution you diluted in the Erlenmeyer flask. Recall from the Procedures that there are 20 mg/mL of starch in the 2% solution. Use that to determine the milligrams of starch in the diluted starch solution. Then, divide the milligrams of starch by the total volume of the solution, which includes the water plus the starch solution. Record your results for use in future questions.
a. 2 mg/mL
b. 0.05 mg/mL
c. 0.2 mg/mL
d. 10 mg/mL

Answer 1

Answer:

0.05 mg/mL  ( B )

Explanation:

Given data:

20 mg/ml starch

2% solution = 2g of solute is in 100g of solvent

Determine the new concentration in mg/ml

Dilution equation = C1V1 = C2V2

new concentration ; applying the dilution factor

dilution factor = 1 : 400 ; ( 2 /400 )g = 0.005 g of solute is present in every  100 mL

∴ new concentration = 0.00005 g / 1 mL * ( 1000 mg / 1g ) = 0.05 mg/mL