Chemischer Alkohol-Test
About points...
We associate a certain number of points with each exercise.
When you click an exercise into a collection, this number will be taken as points for the exercise, kind of "by default".
But once the exercise is on the collection, you can edit the number of points for the exercise in the collection independently, without any effect on "points by default" as represented by the number here.
That being said... How many "default points" should you associate with an exercise upon creation?
As with difficulty, there is no straight forward and generally accepted way.
But as a guideline, we tend to give as many points by default as there are mathematical steps to do in the exercise.
Again, very vague... But the number should kind of represent the "work" required.
When you click an exercise into a collection, this number will be taken as points for the exercise, kind of "by default".
But once the exercise is on the collection, you can edit the number of points for the exercise in the collection independently, without any effect on "points by default" as represented by the number here.
That being said... How many "default points" should you associate with an exercise upon creation?
As with difficulty, there is no straight forward and generally accepted way.
But as a guideline, we tend to give as many points by default as there are mathematical steps to do in the exercise.
Again, very vague... But the number should kind of represent the "work" required.
About difficulty...
We associate a certain difficulty with each exercise.
When you click an exercise into a collection, this number will be taken as difficulty for the exercise, kind of "by default".
But once the exercise is on the collection, you can edit its difficulty in the collection independently, without any effect on the "difficulty by default" here.
Why we use chess pieces? Well... we like chess, we like playing around with \(\LaTeX\)-fonts, we wanted symbols that need less space than six stars in a table-column... But in your layouts, you are of course free to indicate the difficulty of the exercise the way you want.
That being said... How "difficult" is an exercise? It depends on many factors, like what was being taught etc.
In physics exercises, we try to follow this pattern:
Level 1 - One formula (one you would find in a reference book) is enough to solve the exercise. Example exercise
Level 2 - Two formulas are needed, it's possible to compute an "in-between" solution, i.e. no algebraic equation needed. Example exercise
Level 3 - "Chain-computations" like on level 2, but 3+ calculations. Still, no equations, i.e. you are not forced to solve it in an algebraic manner. Example exercise
Level 4 - Exercise needs to be solved by algebraic equations, not possible to calculate numerical "in-between" results. Example exercise
Level 5 -
Level 6 -
When you click an exercise into a collection, this number will be taken as difficulty for the exercise, kind of "by default".
But once the exercise is on the collection, you can edit its difficulty in the collection independently, without any effect on the "difficulty by default" here.
Why we use chess pieces? Well... we like chess, we like playing around with \(\LaTeX\)-fonts, we wanted symbols that need less space than six stars in a table-column... But in your layouts, you are of course free to indicate the difficulty of the exercise the way you want.
That being said... How "difficult" is an exercise? It depends on many factors, like what was being taught etc.
In physics exercises, we try to follow this pattern:
Level 1 - One formula (one you would find in a reference book) is enough to solve the exercise. Example exercise
Level 2 - Two formulas are needed, it's possible to compute an "in-between" solution, i.e. no algebraic equation needed. Example exercise
Level 3 - "Chain-computations" like on level 2, but 3+ calculations. Still, no equations, i.e. you are not forced to solve it in an algebraic manner. Example exercise
Level 4 - Exercise needs to be solved by algebraic equations, not possible to calculate numerical "in-between" results. Example exercise
Level 5 -
Level 6 -
Question
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Exercise:
Lange Zeit verwete die Polizei bei Alkoholkontrollen folge chemische Testmethode: bf Ethanol in der Atemluft reagiert mit Kaliumdichromat ceKCrO^-^ in Gegenwart von verdünnter Schwefelsäure zu bf Essigsäure wobei ein Farbumschlag von gelb nach grün beobachtbar ist. Erläutere die chemischen Hergründe dieser Alkoholkontrolle. Stelle dabei die zwei Reaktionsschritte von Ethanol zu Essigsäure mit Lewisformeln dar. center tikzpicturescale. draw ellipse . and .; fill blueopacity. ellipse . and .; draw -. -- -.-; draw -.- arc ::. and .; draw dashed -.- arc ::. and -.; draw .- -- .; fill blue!!cyan -. -- -.- arc ::. and . -- . arc ::. and -.; scopexshiftcm yshift-.cm fill blueopacity. ellipse . and .; fill blueopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill yellow!!redopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill yellow!!redopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm draw yellow ellipse . and .; fill yellowopacity. ellipse . and .; draw yellow-. -- -.-; draw yellow-.- arc ::. and .; draw dashed -.- arc ::. and -.; draw yellow.- -- .; fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blue!!white -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope tikzpicture hspacecm tikzpicturescale. draw ellipse . and .; fill blueopacity. ellipse . and .; draw -. -- -.-; draw -.- arc ::. and .; draw dashed -.- arc ::. and -.; draw .- -- .; fill blue!!cyan -. -- -.- arc ::. and . -- . arc ::. and -.; scopexshiftcm yshift-.cm fill blueopacity. ellipse . and .; fill blueopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill green!!yellowopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill yellow!!redopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm draw yellow ellipse . and .; fill yellowopacity. ellipse . and .; draw yellow-. -- -.-; draw yellow-.- arc ::. and .; draw dashed -.- arc ::. and -.; draw yellow.- -- .; fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blue!!white -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope tikzpicture hspacecm tikzpicturescale. draw ellipse . and .; fill blueopacity. ellipse . and .; draw -. -- -.-; draw -.- arc ::. and .; draw dashed -.- arc ::. and -.; draw .- -- .; fill blue!!cyan -. -- -.- arc ::. and . -- . arc ::. and -.; scopexshiftcm yshift-.cm fill blueopacity. ellipse . and .; fill blueopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill green!!yellowopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill green!!yellowopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm draw yellow ellipse . and .; fill yellowopacity. ellipse . and .; draw yellow-. -- -.-; draw yellow-.- arc ::. and .; draw dashed -.- arc ::. and -.; draw yellow.- -- .; fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blue!!white -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope tikzpicture vspace.cm footnotesizeLinks: Negativer Alkoholtest Mitte: Positiver AT .textperthousand Rechts: Positiver AT .textperthousand center
Solution:
center scalebox.chemfigce H-C:-H:--H-C:-H:--H-OH cOxidationce+ scalebox.chemfigce H-C:-H:--H-C:O:--H cOxidationce+ scalebox.chemfigce H-C:-H:--H-C:O:--O:-H center Ethanol ist ein primärer Alkohol. Er wird bei der Oxidation zu Ethanal und durch eine weitere Oxidaiton zu Essigsäure.Dabei werden ceH und ce abgegeben. center Reduktion: ceCrO^^- + HO+ + - Cr^^+ + HO center ceK+-Ionen sind glqq Zuschauergrqq ceCrO^^- befindet sich in der Redoxreihe relativ weit glqq untengrqq es ist somit ein gutes Oxidationsmittel wird in der Reaktion reduziert und kann ce aufnehmen. Das für die Reaktion benötigte ceHO+ wird über die Schwefelsäure zugeführt. center Gesamtreaktion: vspace.cm scriptsizeceCHOH +KCrO +HSO - CHCHO +CrSO +HO +KSO center Wird also mit der Ausatemluft Ethanoldampf durch diese präparierte Mischung geblasen so wird der Alkohol zu Ethanal Acetaldehyd oxidiert und das orangerote Kaliumdichromat zu grünem ChromIII-sulfat reduziert.
Lange Zeit verwete die Polizei bei Alkoholkontrollen folge chemische Testmethode: bf Ethanol in der Atemluft reagiert mit Kaliumdichromat ceKCrO^-^ in Gegenwart von verdünnter Schwefelsäure zu bf Essigsäure wobei ein Farbumschlag von gelb nach grün beobachtbar ist. Erläutere die chemischen Hergründe dieser Alkoholkontrolle. Stelle dabei die zwei Reaktionsschritte von Ethanol zu Essigsäure mit Lewisformeln dar. center tikzpicturescale. draw ellipse . and .; fill blueopacity. ellipse . and .; draw -. -- -.-; draw -.- arc ::. and .; draw dashed -.- arc ::. and -.; draw .- -- .; fill blue!!cyan -. -- -.- arc ::. and . -- . arc ::. and -.; scopexshiftcm yshift-.cm fill blueopacity. ellipse . and .; fill blueopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill yellow!!redopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill yellow!!redopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm draw yellow ellipse . and .; fill yellowopacity. ellipse . and .; draw yellow-. -- -.-; draw yellow-.- arc ::. and .; draw dashed -.- arc ::. and -.; draw yellow.- -- .; fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blue!!white -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope tikzpicture hspacecm tikzpicturescale. draw ellipse . and .; fill blueopacity. ellipse . and .; draw -. -- -.-; draw -.- arc ::. and .; draw dashed -.- arc ::. and -.; draw .- -- .; fill blue!!cyan -. -- -.- arc ::. and . -- . arc ::. and -.; scopexshiftcm yshift-.cm fill blueopacity. ellipse . and .; fill blueopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill green!!yellowopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill yellow!!redopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm draw yellow ellipse . and .; fill yellowopacity. ellipse . and .; draw yellow-. -- -.-; draw yellow-.- arc ::. and .; draw dashed -.- arc ::. and -.; draw yellow.- -- .; fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blue!!white -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope tikzpicture hspacecm tikzpicturescale. draw ellipse . and .; fill blueopacity. ellipse . and .; draw -. -- -.-; draw -.- arc ::. and .; draw dashed -.- arc ::. and -.; draw .- -- .; fill blue!!cyan -. -- -.- arc ::. and . -- . arc ::. and -.; scopexshiftcm yshift-.cm fill blueopacity. ellipse . and .; fill blueopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill green!!yellowopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill green!!yellowopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm draw yellow ellipse . and .; fill yellowopacity. ellipse . and .; draw yellow-. -- -.-; draw yellow-.- arc ::. and .; draw dashed -.- arc ::. and -.; draw yellow.- -- .; fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blue!!white -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope tikzpicture vspace.cm footnotesizeLinks: Negativer Alkoholtest Mitte: Positiver AT .textperthousand Rechts: Positiver AT .textperthousand center
Solution:
center scalebox.chemfigce H-C:-H:--H-C:-H:--H-OH cOxidationce+ scalebox.chemfigce H-C:-H:--H-C:O:--H cOxidationce+ scalebox.chemfigce H-C:-H:--H-C:O:--O:-H center Ethanol ist ein primärer Alkohol. Er wird bei der Oxidation zu Ethanal und durch eine weitere Oxidaiton zu Essigsäure.Dabei werden ceH und ce abgegeben. center Reduktion: ceCrO^^- + HO+ + - Cr^^+ + HO center ceK+-Ionen sind glqq Zuschauergrqq ceCrO^^- befindet sich in der Redoxreihe relativ weit glqq untengrqq es ist somit ein gutes Oxidationsmittel wird in der Reaktion reduziert und kann ce aufnehmen. Das für die Reaktion benötigte ceHO+ wird über die Schwefelsäure zugeführt. center Gesamtreaktion: vspace.cm scriptsizeceCHOH +KCrO +HSO - CHCHO +CrSO +HO +KSO center Wird also mit der Ausatemluft Ethanoldampf durch diese präparierte Mischung geblasen so wird der Alkohol zu Ethanal Acetaldehyd oxidiert und das orangerote Kaliumdichromat zu grünem ChromIII-sulfat reduziert.
Meta Information
Exercise:
Lange Zeit verwete die Polizei bei Alkoholkontrollen folge chemische Testmethode: bf Ethanol in der Atemluft reagiert mit Kaliumdichromat ceKCrO^-^ in Gegenwart von verdünnter Schwefelsäure zu bf Essigsäure wobei ein Farbumschlag von gelb nach grün beobachtbar ist. Erläutere die chemischen Hergründe dieser Alkoholkontrolle. Stelle dabei die zwei Reaktionsschritte von Ethanol zu Essigsäure mit Lewisformeln dar. center tikzpicturescale. draw ellipse . and .; fill blueopacity. ellipse . and .; draw -. -- -.-; draw -.- arc ::. and .; draw dashed -.- arc ::. and -.; draw .- -- .; fill blue!!cyan -. -- -.- arc ::. and . -- . arc ::. and -.; scopexshiftcm yshift-.cm fill blueopacity. ellipse . and .; fill blueopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill yellow!!redopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill yellow!!redopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm draw yellow ellipse . and .; fill yellowopacity. ellipse . and .; draw yellow-. -- -.-; draw yellow-.- arc ::. and .; draw dashed -.- arc ::. and -.; draw yellow.- -- .; fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blue!!white -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope tikzpicture hspacecm tikzpicturescale. draw ellipse . and .; fill blueopacity. ellipse . and .; draw -. -- -.-; draw -.- arc ::. and .; draw dashed -.- arc ::. and -.; draw .- -- .; fill blue!!cyan -. -- -.- arc ::. and . -- . arc ::. and -.; scopexshiftcm yshift-.cm fill blueopacity. ellipse . and .; fill blueopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill green!!yellowopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill yellow!!redopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm draw yellow ellipse . and .; fill yellowopacity. ellipse . and .; draw yellow-. -- -.-; draw yellow-.- arc ::. and .; draw dashed -.- arc ::. and -.; draw yellow.- -- .; fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blue!!white -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope tikzpicture hspacecm tikzpicturescale. draw ellipse . and .; fill blueopacity. ellipse . and .; draw -. -- -.-; draw -.- arc ::. and .; draw dashed -.- arc ::. and -.; draw .- -- .; fill blue!!cyan -. -- -.- arc ::. and . -- . arc ::. and -.; scopexshiftcm yshift-.cm fill blueopacity. ellipse . and .; fill blueopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill green!!yellowopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill green!!yellowopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm draw yellow ellipse . and .; fill yellowopacity. ellipse . and .; draw yellow-. -- -.-; draw yellow-.- arc ::. and .; draw dashed -.- arc ::. and -.; draw yellow.- -- .; fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blue!!white -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope tikzpicture vspace.cm footnotesizeLinks: Negativer Alkoholtest Mitte: Positiver AT .textperthousand Rechts: Positiver AT .textperthousand center
Solution:
center scalebox.chemfigce H-C:-H:--H-C:-H:--H-OH cOxidationce+ scalebox.chemfigce H-C:-H:--H-C:O:--H cOxidationce+ scalebox.chemfigce H-C:-H:--H-C:O:--O:-H center Ethanol ist ein primärer Alkohol. Er wird bei der Oxidation zu Ethanal und durch eine weitere Oxidaiton zu Essigsäure.Dabei werden ceH und ce abgegeben. center Reduktion: ceCrO^^- + HO+ + - Cr^^+ + HO center ceK+-Ionen sind glqq Zuschauergrqq ceCrO^^- befindet sich in der Redoxreihe relativ weit glqq untengrqq es ist somit ein gutes Oxidationsmittel wird in der Reaktion reduziert und kann ce aufnehmen. Das für die Reaktion benötigte ceHO+ wird über die Schwefelsäure zugeführt. center Gesamtreaktion: vspace.cm scriptsizeceCHOH +KCrO +HSO - CHCHO +CrSO +HO +KSO center Wird also mit der Ausatemluft Ethanoldampf durch diese präparierte Mischung geblasen so wird der Alkohol zu Ethanal Acetaldehyd oxidiert und das orangerote Kaliumdichromat zu grünem ChromIII-sulfat reduziert.
Lange Zeit verwete die Polizei bei Alkoholkontrollen folge chemische Testmethode: bf Ethanol in der Atemluft reagiert mit Kaliumdichromat ceKCrO^-^ in Gegenwart von verdünnter Schwefelsäure zu bf Essigsäure wobei ein Farbumschlag von gelb nach grün beobachtbar ist. Erläutere die chemischen Hergründe dieser Alkoholkontrolle. Stelle dabei die zwei Reaktionsschritte von Ethanol zu Essigsäure mit Lewisformeln dar. center tikzpicturescale. draw ellipse . and .; fill blueopacity. ellipse . and .; draw -. -- -.-; draw -.- arc ::. and .; draw dashed -.- arc ::. and -.; draw .- -- .; fill blue!!cyan -. -- -.- arc ::. and . -- . arc ::. and -.; scopexshiftcm yshift-.cm fill blueopacity. ellipse . and .; fill blueopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill yellow!!redopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill yellow!!redopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm draw yellow ellipse . and .; fill yellowopacity. ellipse . and .; draw yellow-. -- -.-; draw yellow-.- arc ::. and .; draw dashed -.- arc ::. and -.; draw yellow.- -- .; fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blue!!white -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope tikzpicture hspacecm tikzpicturescale. draw ellipse . and .; fill blueopacity. ellipse . and .; draw -. -- -.-; draw -.- arc ::. and .; draw dashed -.- arc ::. and -.; draw .- -- .; fill blue!!cyan -. -- -.- arc ::. and . -- . arc ::. and -.; scopexshiftcm yshift-.cm fill blueopacity. ellipse . and .; fill blueopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill green!!yellowopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill yellow!!redopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm draw yellow ellipse . and .; fill yellowopacity. ellipse . and .; draw yellow-. -- -.-; draw yellow-.- arc ::. and .; draw dashed -.- arc ::. and -.; draw yellow.- -- .; fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blue!!white -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope tikzpicture hspacecm tikzpicturescale. draw ellipse . and .; fill blueopacity. ellipse . and .; draw -. -- -.-; draw -.- arc ::. and .; draw dashed -.- arc ::. and -.; draw .- -- .; fill blue!!cyan -. -- -.- arc ::. and . -- . arc ::. and -.; scopexshiftcm yshift-.cm fill blueopacity. ellipse . and .; fill blueopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill green!!yellowopacity. -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill green!!yellowopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm draw yellow ellipse . and .; fill yellowopacity. ellipse . and .; draw yellow-. -- -.-; draw yellow-.- arc ::. and .; draw dashed -.- arc ::. and -.; draw yellow.- -- .; fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blue!!white -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopexshiftcm yshift-.cm fill blackopacity. -. -- -.-. arc ::. and . -- . arc ::. and -.; scope scopeyshift-.cm fill yellow -. -- -.- arc ::. and . -- . arc ::. and -.; scope tikzpicture vspace.cm footnotesizeLinks: Negativer Alkoholtest Mitte: Positiver AT .textperthousand Rechts: Positiver AT .textperthousand center
Solution:
center scalebox.chemfigce H-C:-H:--H-C:-H:--H-OH cOxidationce+ scalebox.chemfigce H-C:-H:--H-C:O:--H cOxidationce+ scalebox.chemfigce H-C:-H:--H-C:O:--O:-H center Ethanol ist ein primärer Alkohol. Er wird bei der Oxidation zu Ethanal und durch eine weitere Oxidaiton zu Essigsäure.Dabei werden ceH und ce abgegeben. center Reduktion: ceCrO^^- + HO+ + - Cr^^+ + HO center ceK+-Ionen sind glqq Zuschauergrqq ceCrO^^- befindet sich in der Redoxreihe relativ weit glqq untengrqq es ist somit ein gutes Oxidationsmittel wird in der Reaktion reduziert und kann ce aufnehmen. Das für die Reaktion benötigte ceHO+ wird über die Schwefelsäure zugeführt. center Gesamtreaktion: vspace.cm scriptsizeceCHOH +KCrO +HSO - CHCHO +CrSO +HO +KSO center Wird also mit der Ausatemluft Ethanoldampf durch diese präparierte Mischung geblasen so wird der Alkohol zu Ethanal Acetaldehyd oxidiert und das orangerote Kaliumdichromat zu grünem ChromIII-sulfat reduziert.
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