232k views
3 votes
1.00 mL of blood serum was diluted to 25.00 mL in each fl ask of a standard addition experiment like Figure 5-7 to measure a hormone with a molecular mass of 373 g/mol. The x-intercept of the graph was 4.2 ppb (parts per billion). Find the concentration of hormone in the serum and express your answer in ppb and molarity. Assume that the density of serum and all solution

1 Answer

5 votes

To find the concentration of the hormone in the serum, use the x-intercept of the graph and the dilution factor. Convert the concentration from ppb to molarity using the molecular mass of the hormone. The concentration is 105 ppb and 2.82 x 10^-4 M.

To find the concentration of the hormone in the serum, we can use the x-intercept of the graph, which is given as 4.2 ppb (parts per billion). Since the dilution factor is 25 (25 mL of final volume / 1 mL of initial volume), we can multiply the x-intercept by the dilution factor to get the concentration in ppb: 4.2 ppb x 25 = 105 ppb.

To convert this to molarity, we need to know the molecular mass of the hormone, which is given as 373 g/mol. We can use this information to convert ppb to molarity.

To convert ppb to molarity, we divide the concentration in ppb by the molar mass of the hormone and then multiply by 10^9 to account for the units. Therefore, the concentration in molarity is: (105 ppb / 373 g/mol) x 10^9 = 2.82 x 10^-4 M. So, the concentration of the hormone in the serum is 105 ppb and 2.82 x 10^-4 M.

User Suvi Vignarajah
by
8.2k points