New answers tagged home-experiment
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A rubber balloon does require some force to get filled. A mylar balloon (typically filled with helium) can be purchased empty (or can be emptied) and requires almost no force to fill; then can be squashed manually to eject the gas. They are available in many sizes.
Rubber balloons also tend to go flat or leak, so their storage utility, especially for low m....
1
The use of dry NaHCO3 to extinguish a fire works in two ways:
First, the smothering of the flame with CO2 and water per the decomposition reaction:
$\ce{2NaHCO3 ⟶ Na2CO3 + CO2 + H2O}$
Second, the decomposition reaction is endothermic, so it lowers the temperature of the fire. To quote a source:
In an endothermic reaction heat must be continuously ...
1
When heated, $\ce{NaHCO_3}$ is easily decomposed and produces much $\ce{CO_2}$ in the chemical reaction : $$\ce{2 NaHCO_3 -> Na_2CO_3 + CO_2 + H_2O}$$ and $\ce{CO_2}$ is a gas that tends to prevent Oxygen from maintaining the fire. As to your question 2, I have no idea how to solve it. And as to your question 3, $\ce{NaHCO_3}$ is by far the best ...
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One path to safely determine the strength of H2O2 is:
First dilute it to 1/3 strength (this is for safety when dealing with higher concentrations of hydrogen peroxide).
Slowly titrate against a known concentration of NaOCl until the vigorous oxygen liberation ceases.
One can also collect the volume of O2 evolved.
Reaction equation:
$\ce{NaOCl + H2O2 -> ...
4
Curcumin(the active ingredient in Turmeric) can turn red in two ways: Either by acting as an acid-base indicator or by forming a complex with a phospholipid film, as you stated.
Colour change due to Acid-Base action
The curcumin molecule is a tribasic acid in basic solution, where it exists as its enol tautomer. The loss of one or more protons from the ...
1
Don't use the organics!
This will severely mess up your titration because both permanganates as well as H2O2 will oxidize the carboxylic acids into explosive or corrosive things like peroxyacids (-C(O)OOH). Carboxylic acids are also usually weak, and the peroxy versions can be up to 1000 times weaker.
On the bright side, HCl is a strong acid, and you ...
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To prepare copper acetate absence H2O2, employ a known method from hydrometallurgy to process copper ore employing aqueous ammonia, air (a source of oxygen) and a small amount of salt (acting as an electrolyte for this, in part, spontaneous electrochemical reaction detailed below). This results in tetra-ammine copper hydroxide. The latter exists only in ...
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With styrofoam balls and toothpicks:
Pick a central ball. As an aid for the next step draw three mutually perpendicular great circles on this ball, dividing it into octants.
Pick any octant and the three octants catty-corner to it and place toothpicks through the center of each of these octants. This should give a good approximation of the proper angles ...
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This one is inspired by ideas from Ed V and Todd Minehardt. The cool thing is that the angles are pretty accurate if the chop sticks reach into the opposite corners of the cube:
As a bonus, you can make an octahedral model if you make holes in the center of each square (or slightly offset so that the chop sticks can pass in the center of the cube).
The ...
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Inflate balloons, and tie them «at their stem» like a bouquet of flowers. If you take four of them, not too much inflated, you well demonstrate a situation close to $sp^3$ hybridization. These models equally work well in larger lecture halls by the way, and intentionally using different colors allows many options.
(source)
(screen photo
You need some ...
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You may also use two pairs of compasses, and join them with their tips in opposite directions.
Or you can use your hands wide opened in front of your face. You then turn one of your hands at an angle of 90°, and joined them, without closing them. The thumbs and the two forefingers represent the directions of the four bonds around a carbon atom in $CH_4$.
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The simplest way of checking the nature of your water is related to the difference in density. If you dissolve $80$ g NaCl in $1$ liter ordinary water $H_2O$, you obtain a solution with a density $1.056$ g/mL. You may add a little bit of an ink to make the demonstration more visual. Now you pick up maybe 1 mL of this NaCl solution with a pipette, and let ...
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There is a slight deviation in the literature as to what the hybrid composites are.
Originally, materials were considered hybrid composites if both inorganic (e.g. clay/silicates as the hydrophilic component) and organic (e.g. organic polymer as the hydrophobic component) constituents were involved in building up the matrix (see e.g. a review [1]).
Another ...
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