Sub-category |
Demo Name |
Brief Description |
Demo Notes |
Demo # |
Type of Item |
Colligative
Properties of Solutions |
Osmotic
pressure of a sugar solution |
Regular: put dark or colored corn syrup in thistle
tube and put a soaked membrane over the end using twist ties. Hook it onto a ring stand and into a beaker
of water to observe the solution going up in the tube with time. (See variations in details.) |
Also
on Shakhashiri tape III #42. Small
scale: uses a copper sulfate solution
where you add crystals of sodium hexacyanoferrate(II) and a brown
semipermeable membrane is formed, water enters the membrane, it swells,
bursts, throws out the concentrated sodium hexacyanoferrate(II) solution,
which reacts with copper in solution to make more copper
hexacyanoferrate(II), making solid brown streamers and membranes. It is done on the overhead and looks like
growing sea grass. I tried it out and
it grew 1/2 inch in 5 minutes. I
couldn't really see the membranes bursting and they are small balls, but it
looked kind of neat anyway. |
76 |
Demonstration |
Colligative
Properties of Solutions |
Colligative Properties - melting points |
watch glasses on an overhead or beakers contain ice or ice that
had salt poured on it to show the different melting rates |
|
100 |
Demonstration |
Colligative
Properties of Solutions |
sugar,
diet coke |
A
coke can is opened and heated to evaporate the water leaving the sugary
residue. |
|
150 |
Demonstration |
Colligative
Properties of Solutions |
Osmotic pressure of a sugar solution |
|
Shakhashiri tape III #42. |
M58 |
Movie |
Colloids |
Formation
of a colloid |
Sterno-alcohol
gel; thixotropy, dilatancy. Liquids
are mixed to give a gel which can be lighted |
|
38 |
Demonstration |
Colloids |
Tyndal effect-chemical sunset on overhead projector |
Na thiosulfate and HCl; disproportionation. Can be tricky. A cardboard sheet containing a small hole
is placed on the overhead projector. A
solution is added to beaker containing a different solution which changes the
color of the light projected to resemble a sun set. |
|
65 |
Demonstration |
Colloids |
Cuprammonium
rayon |
|
|
118 |
Demonstration |
Dissolution
Processes |
Solubility, polar and nonpolar solvents |
water, toluene, NaCl, naphthalene; Solubility of solids in
liquids, temperature. Add the two
solids to 4 beakers of the solvents to see what dissolves in what. Do not add too much solid or all won't
dissolve. Solubility of a limestone
rock in 1M HCl, salt in water. |
|
109 |
Demonstration |
Electrolytes
and Non-Electrolytes |
Electrical
conductivity of liquids |
Light
bulb with H2O, acetic acid, K2CrO4. A
beaker is covered with a Petri plate lid containing the 2 copper
electrodes. The electrodes are
immersed into assorted solutions to test whether they light a bulb, and how
brightly. |
|
56 |
Demonstration |
Rates
of Dissolution and Saturation |
Supersaturation-sodium acetate crystallization |
A supersaturated solution of sodium acetate is in a long glass
tube. A single solid crystal causes
the solution to solidify. OR pour the
solution onto a surface containing a crystal and the solution forms a
stalagmite. |
Also see 163 for other crystals, and 146 for other exothermic
reactions. Also on Shakhashiri tape
III #41; Close up on Chemistry Ealy 1:19 (1:21 min) |
106 |
Demonstration |
Rates
of Dissolution and Saturation |
Crystal
formations |
Saturated
solutions form crystals, several variations including waterglass. |
Chemical
garden, microcrystals, sugar and salt, other crystal formations |
163 |
Demonstration |
Rates
of Dissolution and Saturation |
Supersaturation-sodium acetate crystallization |
A supersaturated solution of sodium acetate is in a long glass
tube. A single solid crystal causes
the solution to solidify. OR pour the
solution onto a surface containing a crystal and the solution forms a
stalagmite. |
Shakhashiri tape III #41; Close up on Chemistry Ealy 1:19 (1:21
min) (For Ealy set timer to zero when
first text rolls on screen.) |
M36 |
Movie |
Solubility
rules |
Disappearing
ink, invisible writing, Goldenrod messages |
EtOH,
thymolphthalein, NaOH; The wet ink
looks dark blue but it quickly becomes colorless on paper. Various invisible inks are made for signs,
etc. Some brands of Goldenrod colored
copy paper turn red when sprayed with household ammonia (write first with
white wax or invisible tape) |
|
53 |
Demonstration |
|
Solubility of a gas: Ammonia fountain |
dissolves in water, water fills up inverted flask |
Tricky to set up, but it works--unknown if students liked it
much. Also on Shakhashiri tape 1
#3,4,6; Close up on Chemistry Ealy 16:04 (2 min) |
33 |
Demonstration |
|
Solubility
of a gas: Ammonia fountain |
dissolves
in water, water fills up inverted flask |
Shakhashiri
tape 1 #3,4,6 |
M10 |
Movie |
|
Solubility of a gas: Ammonia fountain |
dissolves in water, water fills up inverted flask |
Close up on Chemistry Ealy 16:04 (2 min) (Set timer to zero when first text rolls on
screen.) |
M11 |
Movie |
Electrolytes
and Non-Electrolytes |
Plastic
Easter eggs as models for dissociation |
|
|
107 |
Demonstration |
Electrolytes
and Non-Electrolytes |
glowing electric pickle-UT, the eyes of Texas are upon you |
UT is spelled out on a plastic grid using specially wired
pickles. The wires are plugged in
causing the pickles to glow yellow orange.
A smaller version uses a single pickle stuck on nails of a board. |
The small version can be available routinely, but the larger
version takes a longer prep time-at least 1 hour. Can have class sing the eyes of Texas while
UT pickle glowing. |
135 |
Demonstration |
Solubility
rules |
Limiting
reactant concept (PbCrO4) |
Potassium
chromate and lead nitrate give a thick yellow precipitate. One reactant is diluted to show the ppt decreases. |
Also
illustrated by Dr. Laude using 6 bolts, 4 nuts, 12 washers on an overhead
projector (See demo #152) |
2 |
Demonstration |
Solubility
rules |
Precipitation reactions |
various 2 clear solutions are mixed to give different colored
precipitates. K2CrO4 + Pb(NO3)2 for
yellow, (NH4)2CO3 + CaCl2 for white.
The barium hydroxide/sulfuric acid ppt can be used with
phenolphthalene to show an acid/base ppt. |
Very popular-The potassium chromate, lead nitrate reaction gives
a thick yellow ppt. (Also see #2 for
limiting reactant using ppt) |
71 |
Demonstration |
Solubility
rules |
Equilibrium
by diffusion of coloring in water |
add
drops of coloring to a big beaker of water, let it sit and become uniform,
notice the mixing of the color throughout class |
|
93 |
Demonstration |
Solubility
rules |
Supersaturation-sodium acetate crystallization |
A supersaturated solution of sodium acetate is in a long glass
tube. A single solid crystal causes
the solution to solidify. OR pour the
solution onto a surface containing a crystal and the solution forms a
stalagmite. |
Also see 163 for other crystals, and 146 for other exothermic
reactions. Also on Shakhashiri tape
III #41; Close up on Chemistry Ealy 1:19 (1:21 min) |
106 |
Demonstration |
Solubility
rules |
Solubility,
polar and nonpolar solvents |
water,
toluene, NaCl, naphthalene; Solubility of solids in liquids,
temperature. Add the two solids to 4
beakers of the solvents to see what dissolves in what. Do not add too much solid or all won't
dissolve. Solubility of a limestone
rock in 1M HCl, salt in water. |
|
109 |
Demonstration |
Solubility
rules |
Crystal formations |
Saturated solutions form crystals, several variations including
waterglass. |
Chemical garden, microcrystals, sugar and salt, other crystal
formations |
163 |
Demonstration |
Solubility
rules |
Supersaturation-sodium
acetate crystallization |
A
supersaturated solution of sodium acetate is in a long glass tube. A single solid crystal causes the solution
to solidify. OR pour the solution onto
a surface containing a crystal and the solution forms a stalagmite. |
Shakhashiri
tape III #41; Close up on Chemistry Ealy 1:19 (1:21 min) (For Ealy set timer to zero when first text
rolls on screen.) |
M36 |
Movie |
|
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