![TheRunningPotatoe245](/avatars/48497.jpg)
TheRunningPotatoe245
11.06.2020 •
Chemistry
A 20.0-mL sample of lake water was acidified with nitric acid and treated with excess KSCN to form a red complex (KSCN itself is colorless). The solution was then diluted to 50.0-mL and put in a 1.00 cm pathlength cell, where it yielded an absorbance of 0.345. For comparison, a 5.0-mL reference sample of 4.80 x 10-4 M Fe3 was treated with HNO3 and KSCN and diluted to 50.0 mL. The reference solution was also placed in a 1.00-cm cell and gave an absorbance of 0.512. What is the concentration of Fe3 in Jordan Lake
Solved
Show answers
More tips
- S Sport How to Learn to Pull Up on Monkey Bars?...
- L Leisure and Entertainment Scrapbooking: What is it and Why is it Becoming More Popular?...
- H Horoscopes, Magic, Divination How to Cast a Love Spell on a Guy? Guide for Guys...
- F Family and Home How to Sew Curtain Tapes: Best Tips from Professionals...
- S Style and Beauty How are artificial nails removed?...
- S Style and Beauty How to Make Your Lips Fuller? Ideas and Tips for Beautiful Lips...
- F Food and Cooking The Disease That Haunted Abraham Lincoln...
- C Computers and Internet How to Get Rid of Windows Genuine Check?...
- H Health and Medicine How to perform artificial respiration?...
- S Style and Beauty Tricks and Tips: How to Get Rid of Freckles...
Answers on questions: Chemistry
- C Chemistry 3. How many atoms of hydrogen (H), sulfur (S), and oxygen (O) are there in sulfuric acid, H2SO?...
- C Chemistry Amber is a weather reporter which field of science is ambers job most closely related to...
- C Chemistry Whhy is it said that sunlight provides energy either directly or indirectly...
- C Chemistry A gaseous substance turns directly into a solid. Which term describes this change? O deposition O evaporation O melting O sublimation...
- C Chemistry What is the net ionic equation of Al2(SO4)3(aq) + 2K3PO4 (aq) = 2AlPO4 (s) + 3K2SO4 (aq)?...
- C Chemistry Interpret the electron configuration...
- C Chemistry Enumere dos desventajas del uso de los combustibles fósiles. Ayud es para hoy :(...
- C Chemistry Body temperature is about 309 K. On a cold day, what volume of air at 264 K must a person with a lung capacity of 2.5 L breathe in to fill the lungs? A) 2.93 L B) 2.14 L C) 2.31 L...
- C Chemistry Los átomos de cierto elemento de transición del cuarto periodo presenta 6 electrones desapareados. Determinar a qué grupo de la tabla pertenece...
- C Chemistry If 12.8g of chlorine gas is reacted with 8.3g sodium iodide, how much sodium chloride will be produced?...
Ответ:
8.09x10⁻⁵M of Fe³⁺
Explanation:
Using Lambert-Beer law, the absorbance of a sample is proportional to its concentration.
In the problem, the Fe³⁺ is reacting with KSCN to produce Fe(SCN)₃ -The red complex-
The concentration of Fe³⁺ in the reference sample is:
4.80x10⁻⁴M Fe³⁺ × (5.0mL / 50.0mL) = 4.80x10⁻⁵M Fe³⁺
Because reference sample was diluted from 5.0mL to 50.0mL.
That means a solution of 4.80x10⁻⁵M Fe³⁺ gives an absorbance of 0.512
Now, as the sample of the lake gives an absorbance of 0.345, its concentration is:
0.345 × (4.80x10⁻⁵M Fe³⁺ / 0.512) = 3.23x10⁻⁵M.
As the solution was diluted from 20.0mL to 50.0mL, the concentration of Fe³⁺ in Jordan lake is:
3.23x10⁻⁵M Fe³⁺ × (50.0mL / 20.0mL) = 8.09x10⁻⁵M of Fe³⁺
Ответ:
The tenement was the size of an triangular yard space with dim light as an average cellar.
Explanation:
(passage below)
"I counted the other day the little ones, up to ten years or so, in a Bayard Street tenement that for a yard has a triangular space in the center with sides fourteen or fifteen feet long, just room enough for a row of ill-smelling closets [toilets] at the base of the triangle and a hydrant at the apex [highest point]. There was about as much light in this “yard” as in the average cellar. I gave up my self-imposed task in despair when I had counted one hundred and twenty-eight in forty families. . . . "