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Experimental synthesis

Part i. synthesis of gold nanoparticles (demo)

Chemicals

1.0 mM HAuCl 4 size 12{ ital "HAuCl" rSub { size 8{4} } } {} (stored in amber bottle)

  • 1% trisodium citrate dihydrate solution

Nanoparticle synthesis

  • Add 20 mL of 1.0 mM HAuCl 4 size 12{ ital "HAuCl" rSub { size 8{4} } } {} to a 50 mL Erlenmeyer flask on a stirring hot plate. Add a magnetic stir bar and bring the solution to a boil
    The TA’s need to be told to add the citrate as soon as the reaction boils or the solution turns colorless.
    .
  • Add 2 mL of 1% trisodium citrate dihydrate solution and observe the properties.

Part ii. synthesis of the aqueous ferrofluid (procedure modified from j. chem. edu. 1999, 76, 943-948.)

Chemicals

1 M FeCl 3 size 12{ ital "FeCl" rSub { size 8{3} } } {} in 2 M HCl Solution:

2 M FeCl 2 size 12{ ital "FeCl" rSub { size 8{2} } } {} in 2 M HCl Solution

  • 25% tetramethylammonium hydroxide in water

1.0 M NH 3 size 12{ ital "NH" rSub { size 8{3} } } {} Solution: Dilute at least 200 mL of concentrated ammonium hydroxide with water to 3.0 L) Open containers of ammonia are odorous and their concentration will decrease over periods of time.

CAUTION: Ferrofluids can be messy. This particular ferrofluid will permanently stain almost all fabrics. Also DO NOT LET THE MAGNETITES TOUCH THE SURFACE OF THE MAGNET DIRECTLY.

Magnetite synthesis

  • In a hood, place 4.0 mL of 1M FeCl 3 size 12{ ital "FeCl" rSub { size 8{3} } } {} and 1.0 mL of 2M FeCl 2 size 12{ ital "FeCl" rSub { size 8{2} } } {} solution into a 100 mL beaker. Stir on a magnetic stir plate.
  • While stirring, slowly add 50 mL of 1.0 M aqueous NH 3 size 12{ ital "NH" rSub { size 8{3} } } {} solution over a 5 minute period using a buret. Initially a brown precipitate will form followed by a black precipitate, which is magnetite.
  • CAUTION: Even though 1M NH3 is fairly dilute, NH 3 size 12{ ital "NH" rSub { size 8{3} } } {} is a strong base.
  • Remove from stirring and immediately use a strong magnet to work the stir bar up the walls of the beaker. Remove the stir bar with a gloved hand being careful not to let it touch the magnet.
  • Allow the magnetite to settle, then decant off the clear liquid into a waste beaker without losing a large amount of precipitate. The settling process can be expedited by placing a strong magnet below the beaker.
  • Transfer the solid to a plastic weighing boat. Rinse out the beaker with a wash bottle.
  • Use a strong magnet to attract the ferrofluid to the bottom of the weigh boat. Carefully decant as much clear liquid as possible into the waste beaker. Rinse again with water from the wash bottle and decant. Repeat the rinsing process a third time. What are you removing by rinsing?
  • Add 1-2 mL of 25% tetramethylammonium hydroxide. Gently stir the solution with a glass stir rod for at least a minute to suspend the solid in the liquid. Use a strong magnet to attract the ferrofluid to the bottom of the weigh boat. Pour off and discard the dark liquid. Move the strong magnet around and again pour off any liquid. If the ferrofluid does not produce spikes, continue to move the strong magnet around, pouring off any liquid.

Ferrrofluid properties

  • Hold a magnet underneath the weigh boat that contains the ferrofluid. Move the magnet around the underside of the weigh boat. Move the magnet close to and far from the weigh boat. Record your observations
  • Add a couple of drops of ferrofluid to a small piece of clean paper. Let the solution dry. Once it is dry, bring a strong magnet close to the paper. What happens?
  • Use several different magnets to observe the properties of the ferrofluid and record your observations in your notebook.

Questions & Answers

show that the set of all natural number form semi group under the composition of addition
Nikhil Reply
what is the meaning
Dominic
explain and give four Example hyperbolic function
Lukman Reply
_3_2_1
felecia
⅗ ⅔½
felecia
_½+⅔-¾
felecia
The denominator of a certain fraction is 9 more than the numerator. If 6 is added to both terms of the fraction, the value of the fraction becomes 2/3. Find the original fraction. 2. The sum of the least and greatest of 3 consecutive integers is 60. What are the valu
SABAL Reply
1. x + 6 2 -------------- = _ x + 9 + 6 3 x + 6 3 ----------- x -- (cross multiply) x + 15 2 3(x + 6) = 2(x + 15) 3x + 18 = 2x + 30 (-2x from both) x + 18 = 30 (-18 from both) x = 12 Test: 12 + 6 18 2 -------------- = --- = --- 12 + 9 + 6 27 3
Pawel
2. (x) + (x + 2) = 60 2x + 2 = 60 2x = 58 x = 29 29, 30, & 31
Pawel
ok
Ifeanyi
on number 2 question How did you got 2x +2
Ifeanyi
combine like terms. x + x + 2 is same as 2x + 2
Pawel
x*x=2
felecia
2+2x=
felecia
×/×+9+6/1
Debbie
Q2 x+(x+2)+(x+4)=60 3x+6=60 3x+6-6=60-6 3x=54 3x/3=54/3 x=18 :. The numbers are 18,20 and 22
Naagmenkoma
Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?
mariel Reply
Mark = x,. Don = 3x + 1 x + 3x + 1 = 113 4x = 112, x = 28 Mark = 28, Don = 85, 28 + 85 = 113
Pawel
how do I set up the problem?
Harshika Reply
what is a solution set?
Harshika
find the subring of gaussian integers?
Rofiqul
hello, I am happy to help!
Shirley Reply
please can go further on polynomials quadratic
Abdullahi
hi mam
Mark
I need quadratic equation link to Alpa Beta
Abdullahi Reply
find the value of 2x=32
Felix Reply
divide by 2 on each side of the equal sign to solve for x
corri
X=16
Michael
Want to review on complex number 1.What are complex number 2.How to solve complex number problems.
Beyan
yes i wantt to review
Mark
16
Makan
x=16
Makan
use the y -intercept and slope to sketch the graph of the equation y=6x
Only Reply
how do we prove the quadratic formular
Seidu Reply
please help me prove quadratic formula
Darius
hello, if you have a question about Algebra 2. I may be able to help. I am an Algebra 2 Teacher
Shirley Reply
thank you help me with how to prove the quadratic equation
Seidu
may God blessed u for that. Please I want u to help me in sets.
Opoku
what is math number
Tric Reply
4
Trista
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
Sidiki Reply
can you teacch how to solve that🙏
Mark
Solve for the first variable in one of the equations, then substitute the result into the other equation. Point For: (6111,4111,−411)(6111,4111,-411) Equation Form: x=6111,y=4111,z=−411x=6111,y=4111,z=-411
Brenna
(61/11,41/11,−4/11)
Brenna
x=61/11 y=41/11 z=−4/11 x=61/11 y=41/11 z=-4/11
Brenna
Need help solving this problem (2/7)^-2
Simone Reply
x+2y-z=7
Sidiki
what is the coefficient of -4×
Mehri Reply
-1
Shedrak
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Kimberly Reply
Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
August Reply
What is the expressiin for seven less than four times the number of nickels
Leonardo Reply
How do i figure this problem out.
how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
Shanjida
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
s.
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Honors chemistry spring. OpenStax CNX. Mar 10, 2008 Download for free at http://cnx.org/content/col10512/1.9
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