kitchen and chemistry

Why is it that I can find only wrong recipes to make brownies on the net? What? I'm not able to search? Whatever. Here is the true one.

Ingredients:

200 g butter, 300 g flour

300 g sugar, 200 g minced walnut

4 eggs, 400 g dark chocolate

Preparation:

Melt butter and chocolate in a water bath, add sugar and let cool down. Add the eggs and whip the batter. Then add flour and nuts. That's it! Ground the dough on a baking tin and cook it at 180°C for 1/2 hour.

I'm leaving Sweden in two days, next to my building there is a nice bakery owned by a Spanish woman: Marta. She can make delicious croissantes and kindly she gaves to me the recipe!

Ingredients:
1 kg flour
120 g yeast
30 g salt
200 g sugar
ice cold water
0.75 kg butter

Preparation:
Prepare the dough with all the ingredients except the butter and keep it in the fridge for 1 night (or 3 h in the freezer). Ground it with the rolling pin a square shape and cover the surface with butter. Close the edges on it and ground it in a right-angled shape 7 mm thick. Now you have to fold the sheet in 3x3 (tres veces tres) way: you have to fold the right edge to the center till 2/3 the lenght and so on with the other. At the end you obtain a square one third the size of the former rectangle. You have to repeat this operation three times. The most impotant thing is the temperature: the dough must be cold otherwise the butter will melt and leak out. Is good after the second folding to keep the mass in the freezer for a while. At the end you need a 5 mm thick sheet. Cut in triangle 7 cm base and 12 cm height and make a 2 cm cut in the middle of the base.
Now it comes the difficult part: you have to roll up the slice from the base to the tip. Let them double in size.
Spread on them a beaten egg and bake them at 220 °C for 10 - 20 min (depending on the oven).Good luck!

Tools:
4 test tube, 4 rubber stopper, bunsen, glasses, gloves

Reagents:
Fe2C2O4, steel wool

Experiment:
fill the four test tube with Fe2C2O4.H2O (yellow powder) for 1/5. Warm them singly on the flame until the development of a black residue. The eventually formed water condense on the neck should be dry up with soft filter paper. Stop carefully the test tubes ready for the experiment. After showing to the public how easily the steel wool burns in contact with the flame, turn off the bunsen and darken the room. At this point you and your assistant go to the demonstration table and, holding 2 test tubes with the stopper pointing toward the floor, uncork simoultaneously them. A gorgeous red spark rain will develops.

Enlightenment:
warming iron oxalate is developed a pirophoric mixture of FeO, Fe that reacts with air oxigen in highly exotermic reaction to give Fe2O3.

Do you like cod fish? No? I agree with you: it's always chewy and stringy, doesn't matter how you cook it!! That what I was thinking before the "discovery" of this recipe, check this out!!

Ingredients:

300 g cod filet, 1/2 cup bechamel sauce, salt, rosemary, saffron, grated parmesan as much as you like!

Preparation:

Take the cod filet and slice it in not too small pieces. Then pour all the ingredient in a small baking-tin and cook ( keep out an handful of parmesan) in a microwave with grill for a few minutes. When it starts to develop some brownish spots, sprinkle the parmesan on the dish and let it brown. Mmhhhh!!

A friend of mine told me that this blog is not written in correct English, but understandable, anyway I do my best. (If you like travelling you should visit Lisa's blog ).
You like to eat pasta, I know it, but you are bored to have it with tasteless sauces (or worse with ketchup!). Here is the best pasta ever; this recipe is from Lucia, my mum.
Ingredients:
red peppers, eggplants, tomato sauce, onion, (the quantity depends both from the shape of the vegetable and the quantity of pasta you want to cook ). Usually for five person you need 6-700 g of pasta, a couple of eggplants and three or four big peppers ).
Preparation :

Put in a frying pan some olive oil and the sliced eggplants (not too fine). In the first minutes the eggplants will absorb all the oil, but don't add other, they will give it back later .When the eggplants begins to soften and leaks oil, pour in the pan sliced onions and red peppers. Let them fry for a few minutes and than pour in some tomato sauce. Also here only practice can gives you the right amount: we don't want a red sauce, tomatoes should be at most 40 % the mass of the final product. Let it go on weak flame for a few minutes and finally (not before!) add some salt. Meanwhile you have boiled the pasta in salted water; strain it when is still somewhat raw. Pour it in the pan, rise the flame and let it go with the sauce untill it reaches a "to the tooth" texture.
Finally a couple handful of grated parmesan. Mmmmmhh...

Careful : around 100°C , Mn2O7 oxidize in explosive way organic substances ; for this reason you must prevent an overheating of the system .

Tools : 2 test tubes ( 16 x 160 mm ) , 2 supports whith clamps , becher 200 ml , pneumatic bath , glasses , gloves .

Reagents : KMnO4 , H2SO4 conc , ethanol

Experiment : the test tubes are fixed to the supports so as them are dipped in the water bath for about an half .Pour H2SO4 conc in the test tubes for about 2 cm height , then pour 4 cm of ethanol above the acid , avoiding the blending of the 2 fase .Now introduce in each tube a small cristal of KMnO4 , after a while , at the level of the liquids interface , are noticed yellow flash , which develops crackling .It seems that the flashes are produced under the water .
Gradually the mixture goes to green and brown .The experiment can go on for 15 min , during thath time the frequency of the flashes it's unpredictable .

Enlightenment : KMnO4 reacts first with the sulfuric acid to give Mn2O7 , that oxidize the alcol in a violent reaction .

2 KMnO4 + H2SO4 ------- K2SO4 + Mn2O7 + H2O
Mn2O7 ------- 2 MnO2 + 1/2 O2

Treatment : after cooling , neutralize with Ca(OH)2 and pour it in the inorganic salts waste .The water solution can be poured out in the sink .