Question

Based on the recipe for the Dextrose Calcium Carbonate (DCC) medium, what is the percent concentration (%weight/volume) of dextrose? Note: the recipe is based on a final volume of 1 L, not 100 ml. Here is the recipe:5.0g Yeast Extract, 1.0g K2HPO4, 0.5g MgSO4, 20.0g Dextrose (Glucose), 10.g CaCO3, 18.0g Agar, and 1.0 L dH2O

Answer 1

Answer: The percent concentration ( % m/v) of dextrose in the solution is 2 %

Explanation:

We are given:

Mass of Yeast Extract = 5.0 grams

Mass of $K_2HPO_4$ = 1.0 grams

Mass of $MgSO_4$ = 0.5 grams

Mass of Dextrose = 20.0 grams

Mass of $CaCO_3$ = 10. grams

Mass of Agar = 18.0 grams

Volume of solution = 1 L = 1000 mL      (Conversion factor: 1 L = 1000 mL)

% (m/v) is defined as the concentration, which is mass of solute present in 100 mL of solution

To calculate the mass of solute, we apply unitary method:

In 1000 mL of solution, the mass of dextrose present is 20.0 grams

So, in 100 mL of solution, the mass of dextrose present will be = $\frac{20.0}{1000}\times 100=2g$

Calculating the % (m/v) of dextrose, we get:

$\% \text{(m/v) of dextrose}=\frac{\text{Mass of dextrose}}{\text{Volume of solution}}\times 100\\\\\% \text{(m/v) of dextrose}=\frac{2g}{100mL}\times 100=2\%$

Hence, the percent concentration ( % m/v) of dextrose in the solution is 2 %