Europium is a lanthanide element found in parts per billion levels in natural wa

Question

Europium is a lanthanide element found in parts per billion levels in natural waters. It can be measured from the intensity of orange light emitted when a solution is illuminated with ultraviolet radiation. Certain organic compounds that bind Eu(III) are required to enhance the emission. The figure below shows standard addition experiments in which 10.00 mL of a sample and 20.00 mL containing a large excess of organic additive were placed in 50 mL volumetric flasks. Then Eu(III) standards (0, 5.00, 10.00 or 15.00 mL) were added and the flasks were diluted to 50.0 mL with water. Standards added to tap water contained 0.136 ng/mL (ppb) of Eu(III), but those added to pond water were loo times more concentrated. (a) From the x intercepts in the graph, calculate the concentration of Eu(III) (ng/mL) in tap water. ng/mL From the x Intercepts In the graph, calculate the concentration of Eu(III) (ng/mL) in pond water. ng/mL

Explanation / Answer

1) the standard added is of concentration = 0.136ng /mL

From the graph the intercept for tap water is -6.0 mL,

(6.0mL) (0.136 ng/mL) = 0.816ng Eu(III).

the total volume = 10mL

So concentration = Mass / Volume = 0.816ng / 10mL = 0.0816ng /mL

Similary for pond water,intercept of - 14.6 mL , amount will be

(14.6 mL)(13.6ng/mL) = 198.56 ng Eu(III)

Again this amount is in 10mL so the concentration will be = 198.056ng /10mL = 19.856 ng /mL

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.