Answer:
79 extractions
Explanation:
An<em> isooctane/water partinioning constant</em> of 12/1 means that 12 out of 13 parts of the Pb²⁺ complex will be found in isooctane, while the remaining 1 out of 13 part will remain in water.
- 12/13 * 100 = 92.3% of the Pb²⁺ will be removed with each extraction.
Now we <u>convert 1.4 mg/mL to ug/mL</u>:
- 1.4
= 140 ug/mL
We're looking to have a final concentration of 0.25 ug/mL, so we can write:
- 140 mg/mL * (0.923)ⁿ = 0.25 ug/mL
Where <em>n</em> is the number of extractions.
We <u>solve for </u><u><em>n</em></u>:
- n = ln (1.786x10⁻³) / ln (0.923)
This problem is describe the mole-ratio composition of an allow composed by tin, lead and cadmium. Ratios are given as Sn:Pb 2.73:1.00 and Pb:Cd is 1.78:1.00, and we are asked to calculate the mass percent compositon of Pb in the allow.
In this case, according to the given information, it turns out possible realize that the following number of moles are present in the alloy, according to the aforementioned ratios:
Next, we calculate the masses by using each metal's atomic mass:
Thus, the mass percent composition of each metal is shown below:
So that of lead is 34.9 %.
Learn more:
<span>Electromagnetic radiation will be emitted when any
object has a temperature above zero. The
reason behind this is that atoms within any object at a temperature above
absolute zero have energy, and thus is moving.</span>
<span>Atoms are at least partly composed of charged
particles, changed particles must be moving too.</span>
