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- October 16, 2026 at 4:43 am in reply to:Nomenclature, dessin de molécules, 2 (oc-11)Les noms suivants sont donnés pour diverses molécules. Dessinez la molécule à laquelle elle appartient.
- hexane
- 2 méthyl octane
- 3,4-il s'agit de-Ethyl-2,2,5-les décanes tri-méthyl
- L'éthanol (aussi Ethan-1-à l'intérieur)
- Propan-1,2,3-[traduction manquante]
- Butan-1-à la
- Butan-2-sur
- [traduction manquante]
- 4-le méthyl-Pentan-1-à l'intérieur
- 2-le méthyl-Pentan-2-à l'intérieur
- 3-produits à base d'amino-Heptan-1-à l'intérieur
- Butanal à 3-hydroxy
- 2,3-déméthyl-Butan-2,3-diol
- 2,3-diméthyl pentane
- 1-Ethyl-1-le cyclobutan méthyle
- 3-Ethyl-2,2,4-le tri-méthyl-hexane
#5665
Solution: {a) hexane }/\/\/{b) 2-méthyl octane: }@:n(n,a,L:.4)<_(A&a,L&L,N0)$itemColor1(blue)\"&n\">@; @n(8,90)/@n(7,90)\@n(6,90)/@n(5,90)\@n(4,90)/@n(3,90)\@n(2,-90)<|>/@n(1,90){c) 3,4-Di-éthyl
2,2,5-Tri-méthyl décan: }/<_q4><_p4>/<`|/>\<|\>/<`|>\/\/\{d) L’éthanol: }/\OH{(e) Propan-1,2,3-triol:}HO/\<|OH>/\OH{f) Butan-1-à la: }/\/`||O{g) Butan-2-sur:}@:n(n,a,L:.4)<_(A&a,L&L,N0)$itemColor1(blue)\"&n\">@; @n(4,90)/@n(3,90)\@n(2,-90)<||O>/@n(1,90){h) [traduction manquante]}`/`-`\/-\-OH{i) 4-le méthyl-Pentan-1-à l’intérieur}\<|>/\/\OH { } { ou: } HO/\/\<|>/{j) 2-le méthyl-Pentan-2-à l’intérieur}HO/<_q4><_p4>/\/{k) 3-produits à base d’amino-Heptan-1-à l’intérieur}HO\/\<|NH2>/\/\{l) Butanal à 3-hydroxy}\<|OH>/\//O{m) 2,3-déméthyl-butane-2,3-diol }HO-<_q4><_p4>–<_q4><_p4>-OH{n) 2,3-diméthylpentane }/<`|>\<|>/\{o) 1-Ethyl-1-le cyclobutan méthyle }(*`/*)(*`\/*)|-`|_#1{p) 3 – Ethyl-2,2, 4 – Tri-méthyl- hexane }@:n(n,a,L:.4)<_(A&a,L&L,N0)$itemColor1(blue)\"&n\">@; @n(1,90)/@n(2,90)<_(A225)><_(A-45)>\@n(3,-90)<|\>/@n(4,90)<`|>\@n(5,90)/@n(6,90)October 16, 2026 at 4:43 am in reply to:Konjugiert_1 (SB-10)What are conjugate acid-base pairs?
#9595
Solution: Gives a acid sein(e) protons from, so is generated the basic parts (base because it yes theoretically the proton [translation unavailable] to take up could). These couples are called conjugate acid-base pairs.
Example: H3O+ as acid is to H2O. Thus would be H3O+ / H2O the acid-base chemistry-pairs. Trivial but: note, the acid particle (H3O+) appears first.October 16, 2026 at 4:43 am in reply to:Behaviour of an acid or base (SB-03)Formulate reactions for the following given substances. the abbreviation LM stands for solvent.
It is not a question of judging whether The required reactions possible are or not, but that is why, that z.B. At a required acidic reaction the given particles a H+ is emitted and the solvents this and then is absorbed.- (a) HBr, acid reaction, LM: water
- (b) HF, base reaction, LM: water
- (c) HF, acid reaction, LM: water
- (d) HF, acid reaction, LM: NH3
- (e) H2O, acid reaction, LM: water
- (f) CH3COOH, acid reaction, LM: water
- (g) CH3OH, base reaction, LM: NH3
- (h) CH3OH, acid reaction, LM: water
#9593
Solution: - a) HBr + H2O ⇄ Br– + H3O+
- b) HF + H2O ⇄ FH+2 + OH–
- c) HF + H2O ⇄ F– + H3O+
- d) HF + NH3 ⇄ F– + NH+4
- e) H2O + H2O ⇄ OH– + H3O+
- f) CH3COOH + H2O ⇄ CH3COO– + H3O+
- g) CH3OH + NH3 ⇄ CH3OH+2 + NH–2
- h) CH3OH + H2O ⇄ CH3O– + H3O+
October 16, 2026 at 4:43 am in reply to:Acido, neutro e base, indicare la zona (SB-45)Completare i vuoti nella tabella con i valori < 7, = 7, > 7, < 10-7, = 10-7 e > 10-7Nome Soluzione acida Soluzione neutrale Soluzione di base c(H3O+ mol/l) pH c(OH– mol/l) pOH
#7629
Soluzione: Nome Soluzione acida Soluzione neutrale Soluzione di base c(H3O+ mol/l) > 10-7 = 10-7 < 10-7 pH < 7 = 7 > 7 c(OH– mol/l) < 10-7 = 10-7 > 10-7 pOH > 7 = 7 < 7 October 16, 2026 at 4:43 am in reply to:Nomenclature, dessin de molécules, 1 (oc-10)Soient donnés suivantes 6 molécules. L’un d’eux est nettement différent de tous les autres. Qu’est-ce et pourquoi ?{a) } \<|>/<`|>\/\/\{b) } /<`|>\<|>/\/\|{c) } \/\/\<|<`/>\>/{d) } /<`|>\<|>/\/\/{e) } \/\|`/<`\>|<`/>\{f) } \|`/|<`/>\/<`|>\
#5663
Solution: La dernière molécule f) est différente de toutes les autres. a) à e) sont identiques, même si elles ont une apparence différente.
La nomenclature systématique aide clairement à souligner les différences. N’oubliez pas que la numérotation des atomes de carbone ne doit pas nécessairement se faire de gauche à droite, mais de manière à ce que la somme des branches soit aussi petite que possible.{a) } @:n(n,a,L:.4)<_(A&a,L&L,N0)$itemColor1(blue)\"&n\">@; @n(1,-70)\@n(2,50)<|>/@n(3,-30)<`|>\@n(4,50)/@n(5,-50)\@n(6,50)/@n(7,-50)\@n(8,50)2,3-di-méthyl octane {b) } @:n(n,a,L:.4)<_(A&a,L&L,N0)$itemColor1(blue)\"&n\">@; @n(1,80)/@n(2,90)<`|>\@n(3,-90)<|>/@n(4,90)\@n(5,90)/@n(6,-90)\@n(7,45)|@n(8,90)2,3-di-méthyl octane {c) } @:n(n,a,L:.4)<_(A&a,L&L,N0)$itemColor1(blue)\"&n\">@; @n(8,90)\@n(7,90)/@n(6,90)\@n(5,90)/@n(4,90)\@n(3,-90)<|@n(2,90)<`/@n(1,90)>\>/2,3-di-méthyl octane {d) } @:n(n,a,L:.4)<_(A&a,L&L,N0)$itemColor1(blue)\"&n\">@; /<`|@n(1,-90)>@n(2,90)\@n(3,-90)<|>/@n(4,90)\@n(5,90)/@n(6,90)\@n(7,90)/@n(8,90)2,3-di-méthyl octane {e) } @:n(n,a,L:.4)<_(A&a,L&L,N0)$itemColor1(blue)\"&n\">@; @n(8,90)\@n(7,90)/@n(6,90)\@n(5,-90)|@n(4,90)`/@n(3,-90)<`\>|@n(2,90)<`/@n(1,90)>\2,3-di-méthyl octane {f) } @:n(n,a,L:.4)<_(A&a,L&L,N0)$itemColor1(blue)\"&n\">@; @n(8,-90)\@n(7,-90)|@n(6,90)`/@n(5,-90)|<`/>@n(4,90)\@n(3,90)/@n(2,90)<`|@n(1,-90)>\2,4-Di-méthyl octane October 16, 2026 at 4:43 am in reply to:Difference between H and Proton (SB-02)Is an H+ the same as a proton?
#9591
Solution: In the principle yes, ABER respect: it is the proton of a naked hydrogen atoms ('H without electron') means. Per memory: the elements are composed of protons and possibly neutrons (as well as a certain number of electrons). So all the elements also have a certain number of protons, helium, for example, has two protons. These protons to make but NICHT the characteristics a acid from.
Solution: {alcool primaire: } /\/\OH{alcool secondaire: } /<`|OH>\/{alcool tertiaire: } –<|><`|>-OHOctober 16, 2026 at 4:43 am in reply to:Calcolare vari valori (pH, ecc) (SB-44)Calcolare / completare i valori della tabella seguente.c(H3O+ mol/l) c(OH– mol/l) pH pOH 0.001 0.01 0.1 0.2 12 11
#7627
Soluzione: Ricordiamo che il prodotto ionico è valido per ogni concentrazione, per ogni pH o pOH.
prodotto ionico: c(H3O+)·c(OH–) = 10-14 mol2/l2c(H3O+ mol/l) c(OH– mol/l) pH pOH forte{0.001 = 10-3} 10-11 3 11 forte{0.01 = 10-2} 10-12 2 12 10-13 forte{0.1 (10-1)} 13 1 10-14/0.2 = 5·10-14 forte{0.2 } 13.3 0.7 10-12 10-2= 0.01 forte{12} 2 10-3 = 0.001 10-11 3 forte{11} October 16, 2026 at 4:43 am in reply to:Dessinez différents types d’alcool (oc-04)Trois types d'alcool à dessiner:- alcool primaire
- alcool secondaire
- alcool tertiaire
#5659
Solution: - /\OH { } \<|>/\OH { } \/<`|>\/OH
- /\<|HO>/ { } \/<`|OH>\| { } /<`|>\/<`|OH>\/
- OH|_(A75);/#2\ { } OH|_(A75);/#2\/`| { } OH|_(A75);/#2\/\|
October 16, 2026 at 4:43 am in reply to:Definition of acid (SB-01)What is an acid or a base?
#9589
Solution: There are different definitions. The the simplest: a acid is a connection, which H+ (also protons called) payment can, z.B. HF. A base is therefore a substance that can absorb H+.
October 16, 2026 at 4:43 am in reply to:Valore pH 1 (SB-43)Calcolare il pH di una soluzione di acido salico di 3 mo.
#7625
Soluzione: Il pH è il logaritmo negativo (decadico) della concentrazione di H3O+ particelle in una soluzione. La concentrazione deve variare tra 1 mol/l e 10-14 mol/l. Quindi si ottiene un possibile pH di pH = -log 1 = 0 a pH = -log 10-14 = 14.
La risposta (alla domanda) è quindi: non si può dire, poiché la concentrazione è maggiore quando è 1 mol per litro.
Soluzione: A calcoli rotondo per il tematica acidi-basi ha si esso molto spesso con molto piccole concentrazioni a fare, questo corrisponde anche al [traduzione mancante]. Di solito le concentrazioni si muovono da qualche parte nell'area millimulare. Sono ora in aggiunta le concentrazioni il H3O+ considerato, così sono queste spesso ancora piccole, z.B. 0.00001 mol/l o 0.000001 mol/l. Quale delle due concentrazioni è più piccola? E forse si è sbagliato nel contare i zero… faticoso. Se si prende il logaritmo (decadico) e si moltiplica con -1 si ottiene una dimensione che è molto più intuitiva anche nella vita quotidiana in laboratorio.
October 16, 2026 at 4:43 am in reply to:Dessin des groupes fonctionnels différents, 3 (oc-03)Chaque fois, dessinez n'importe quelle molécule qui contient simultanément tous les groupes fonctionnels, la structure de base étant toujours une base d'algues- Alcène, l'alcool et acide carboxylique
- Alcène, aldéhyde, cétone ainsi que amide
- Acide carboxylique, l'alcool et cétone
- Amin, amide, acide carboxylique et Aldeyhd
#5657
Solution: - /<`||>\<|OH>/<`||O>\OH
- H/<`||O>\/\\/<`||O>\/\<||O>/NH2
- HO/<`||O>\<|OH>/<`||O>\
- H2N/\N<_(y.5)H>/<`||O>\<|<`//O>\OH>/<`||O>
October 16, 2026 at 4:43 am in reply to:Temperature dependence of equilibrium constant K (thermo-42)Calculate ΔGoR for the combustion reaction temperatures of 298K, 900K and 2300K from N2 to NO. The given temperatures of 900 K correspond to the temperature in an exhaust or in the combustion chamber (2300K),
Note: Calculate the reaction for 1 particle (respectively 1 mol) NO.
#9587
Solution: The following reaction equation is considered: ½·O2(g) + ½·N2(g) ⇄ NO (g)
Table of values:ΔHof(kJ·mol-1) So(J·K-1·mol-1) O2 (g) 0 205.03 N2 (g) 0 191.61 NOO (g) 90.37 210.62 - reaction equation:
½·O2(g) + ½·N2(g) ⇄ 1·NO (g) - ΔHoR = ∑ΔHof(Produkte) – ∑ΔHof(Edukte)
ΔHoR = (1· ΔHof(NO,g)) – (½· ΔHof(O2, g) + ½· ΔHof(N2,g))
ΔHoR = (90.37) – (½·0 + ½·0) = +90.37 kJ/mol - ΔSoR= So(Produkte) – So(Edukte)
ΔSoR = (1·So(NO,g)) – (½·So(O2, g) + ½·So(N2,g))
ΔSoR = (210.62)-(½·205.03 + ½·191.61) = +12.3 J·mol-1·K-1 - ΔGoR = ΔHoR – T· ΔSoR
ΔGoR(T=298K) = 90.37 – (298)·0.0123 = 86.7 kJ/mol
ΔGoR(T=900K) = 90.37 – (900)·0.0123 = 79.3 kJ/mol
ΔGoR(T=2300K) = 90.37 – (2300)·0.0123 = 62.08 kJ/mol - with dG = -RTln K follows: K = e(-dG/R·T), R=0.008314 kJ/mol·K
ΔGoR(T=298K) = 86.7 kJ/mol → K= 6.34·10-16
ΔGoR(T=900K) = 79.3 kJ/mol → K= 2.5·10-5
ΔGoR(T=2300K) = 62.08 kJ/mol → K= 0.03
Discussion: it acting itself to a endothermal reaction ( ΔHoR > 0). To promote the reaction So an increase in temperature would be necessary. This is through the calculation the equilibrium constant K confirmed: [translation unavailable] higher the temperature is, the more greater is the K-value self. Es shows itself but, that the balance but also at high temperatures always still relative very strong on the page the reactants is, a application of a catalysts offers itself thus at.
October 16, 2026 at 4:43 am in reply to:Des dessins différents groupes fonctionnels, 2 (oc-02)Pour chaque exercice dessinez la formule structurelle. En plus du groupe fonctionnel, aucun autre groupe fonctionnel ne peut être dessiné; seuls les liens carbone-hydrogène sont autorisés.- Un alcool linéaire non branché contenant exactement 3 atomes de carbone
- Un alcool branché avec exactement 5 atomes de carbone
- Toutes les alcools (branchées, non branchées) contenant exactement 4 atomes de carbone
- Trois différentes éther avec chaque au total 4 les atomes de carbone
- Le cétone le moins possible (aussi peu de C que possible)
- L'aldéhyde le moins possible (aussi peu de C que possible)
- Le plus petit possible (le moins de C possible) Amine
- Le plus petit ester possible (aussi peu C que possible)
#5655
Solution: {a) }/\/OH{b) }/\<|>/\OH{c) }/\/\OH { } /<`|>\/OH { } OH|_(A75);/#2\{d) }/O\/\ { } /\O/\ { } -_p_pO_p_p{e) Le plus petit cétone }/<`||O>\{f) le plus petit aldéhyde}H/<`||O>\H { ou: } <`||O>{g) La plus petite amine}H2N/{h) Le plus petit ester}<`|O|>\O/
Soluzione: Principialmente una concentrazione ('numero di particelle per volume'). Al pH si considerano gli H+ (o più precisamente H3O+). Poiché questo numero varia da 1 mol/l a 0.00000000000001 mol/l, si ritiene che In particolare: pH = -log(c[H3O+]).
Affinché risulta si una larghezza di tensione del pH's di -log(1) = -log(100)= 0 fino a a -log(0.00000000000001) = log(10-14)= 14October 16, 2026 at 4:43 am in reply to:Calculate seed temperature (thermo-41)Calculate the boiling point of the water .
#9585
Solution: It shall apply: H2O(l) ⇄ H2O(g).
For this chemical equilibrium is: K = c(H2O(g))/c(H2O(l)) = 1
With dG = -R·T·ln(K) followed by K = 1: dG = 0
Furthermore: dG = dH-T·dS (=0)
thus T = dH/dS- T = dH/dS
ΔHoR = ΔHof(H2O, g) – ΔHof(H2O, l)
ΔHoR = -241.82 – (-285.83) = 44.01 kJ/mol
ΔSoR = So(H2O, g) – So(H2O, l)
ΔSoR = 188.85 – 69.91 = 118.92 J/(mol·K) = 0.11892 kJ(mol·K) - T = dH/dS = 44.01 / 0.11892 = 370 K or Approx. 97℃
The calculated (!) seating temperature of the water is therefore approximately 97℃ The deviation from the usual value of 100℃ is therefore due to the fact that dH or dS actually also (little) depend on the temperature.
October 16, 2026 at 4:43 am in reply to:Produzione di una determinata concentrazione (SB-40)Descrivi la produzione di queste soluzioni in laboratorio: la soluzione è sempre acqua distillata.
Accettazione le sostanze siano come sali presente e dissolvere si completamente in acqua.- a) 1 litri una 0.3 M NaOH-soluzione
- b) 1 litri una 0.4 M HCL-soluzione
- c) 25 ml di soluzione di 0.5 M di NaOH
- d) 30 ml 0.6 M H2SO4
#7619
Soluzione: Le abbreviamento 'M' è un nota su la concentrazione, così cioè: z.B. 0.3 M, che 0.3 mol il i seguenti: substanza in un litro di acqua, in altre parole: 0.3 mol/l
Con c=n/V e n=m/M segue: c=m/M/V rispettivamente m=c·V·M
Rispetto: qui è ora il 'M' la massa molare ! Il dopo situazione sta il 'M' per concentrazione o la massa molare !Procedura per la fabbricazione del soluzione: Il materiale fisso, ad esempio B. NaOH viene pesato, in un B. la distillazione dell'acqua come desiderata. Si noti che il materiale solido richiede un piccolo volume di produzione, ma non è necessario tenerlo conto.
- a) m(NaOH)=c(NaOH)·V·M(NaOH) = 0.3 mol/l · 1.0 l · 58.5 g/mol = 17.55 g
Quindi vengono pesati 17.55 g di NaOH e il bicchiere viene riempito di acqua distillata fino alla marcatura di 1.0 litri. - b) m(HCl)=c(HCl)·V·M(HCl) = 0.4 mol/l· 1.0 l · 36.5 g/mol = 14.6 g
Quindi bisogna pesare 14.6 grammi di HCl e riempire il bicchiere con acqua distillata fino a marcare 1.0 litri. - c) m(NaOH)=c(NaOH)·V·M(NaOH) = 0.5 mol/l · 0.025 l · 58.5 g/mol = 0.73 g
Pesare 0.73 g di NaOH e riempire con questa acqua fino alla marcatura di 25 ml. - d) m(H2SO4) = c(H2SO4) · V · M(H2SO4) = 0.6 mol/l · 0.03 l · 98 g/mol = 1.764 g
Pesare 1.764 g di H2SO4 e riempire con tale acqua fino alla marcatura di 30 ml.
October 16, 2026 at 4:43 am in reply to:Gibbs free energy of reaction, water [translation unavailable] Hydrogen peroxide (thermo-40)Es reacting H2(g) with O2(g). Assessments with help the free reaction enthalpy whether or not well, you know, H2O(g) or H2O2(g) of which: is. The reaction temperature is 800 Kelvin.
#9583
Solution: Es to leave itself two reactions to formulate:
(a) H2(g) + 1/2·O2(g) → H2O(g) and
b) H2(g) + O2(g) → H2O2(g)
Note: In order to compare the results with each other, one must look at the same number and H2O respectively. H2O2 related!Table of values showing that all the particles involved are in a gaseous state:
ΔHof(kJ·mol-1) So(J·K-1·mol-1) H2 (g) 0 131 O2 (g) 0 205 H2O (g) -242 189 H2O2 (g) -136 233 - reaction (a), H2O is produced
[translation unavailable]: ΔHoR = ∑ΔHof(Produkte) – ∑ΔHof(Edukte)
ΔHoR(H2O) = (-242) – (0 + 1/2·0) = -242 kJ/mol
ΔSoR(H2O) = (189) – (131 + 1/2·205) = -44.5 J/(mol·K)
[translation unavailable]: ΔGoR = ΔHoR – T· ΔSoR
ΔGoR(H2O) = -242 – 800·-0.0445 = -206.4 kJ/mol
- reaction b), H2O2 is produced
[translation unavailable]: ΔHoR = ∑ΔHof(Produkte) – ∑ΔHof(Edukte)
ΔHoR(H2O2) = (-136) – (0 + 1/2·0) = -136 kJ/mol
ΔSoR(H2O2) = (233) – (131 + 205) = -103 J/(mol·K)
[translation unavailable]: ΔGoR = ΔHoR – T· ΔSoR
ΔGoR(H2O2) = -136 – 800·-0.103 = -53.6 kJ/mol
The calculation shows that although both reactions would have to be exergonic ( ΔGoR < 0) and therefore voluntary, reaction a) is almost a factor 4 more exergonic and is therefore preferred.
October 16, 2026 at 4:43 am in reply to:Dessinez différents groupes fonctionnels (oc-01)Dessinez à chaque exercice chacun de trois différents molécules, qui ne sont constitués que d'un squelette hydrocarboné (squelette d’alcane, c'est-à-dire liaisons simples) ainsi que du groupe fonctionnel suivant:- Alcanes non branchées
- Alcanes branchées
- Alcanes cycliques
- Alcées
- Alkyne
- L'alcool
- aldéhyde
- cétone
- Amine
- acide carboxylique
- acide aminé
- ester
- amide
#5653
Solution: - Alcanes non branchées\/\ ; { } ; \/\|\ ; { } ; \/\/\/\/
- Alcanes branchées/<`|>\ ; { } ; /<`|>\/ ; { } ; \<|>/\<|>/
- Alcanes cycliques-_q3_q3 ; { } ; /\|`/`\`| ; { } ; _(x1.2,y1)_(x1,y-.5)_(x1,y.5)_(x1.2,y-1)_(x-1.2,y.3)_(x-1,y-.8)_(x-1,y.8)_#1
- Alcées/=/ ; { } ; /\/\// ; { } ; \//\<|>//\
- Alkyne///c/\ ; { } ; -%-/ ; { } ; \\\c\<|>/\/
- L’alcool:\/\|OH ; { } ; \<|>/OH ; { } ; /\OH
- Aldéhyde:\||O ; { } ; O\\|\|`//`\`||/ ; { } ; H\/O`/|\|`/`\`|<_(a-30)><`->/
- Les cétones:/<`||O>\ ; { } ; /\/<`||O>\ ; { } ; /\<||O>/
- Il y a aussi de l’amine./\NH2 ; { } ; /<`|NH2>\/ ; { } ; /\/\/\/NH2
- Les acides carboniques:OH`/|O`| ; { } ; Cl`/|`/N`\\<`/Cl>`|//\|\|O`|/OH ; { } ; HO/`|O|\/\/\|O`|/OH
- Les acides aminés:H2N-CH<|$color(red)CH3>-$color()COOH ; { } ; |`//`\`||/\/`|O|\N<_(y.5)H>/\|O`|/OH ; { } ; \<|>/`|<`\dH2N>/`|O|\OH
- ester:|`//`\`||/\/`|O|\O/\||\//`|`\`/ { } H|`/O/\O/\|`/O|`/O/\H { } /O\|O`|/\/`|O|\O/
- L’amide:H2N/\O { } /\|O`|/N<_(y-.5)H>\ { } -_qNH_q<`|O|>_q_q
October 16, 2026 at 4:43 am in reply to:Interpretazione pKs, 1 (SB-27)Si deve indicare l'acido solforico. il pKs(H2SO4) è -3, pks(HSO–4) = 1.92.
Quale delle seguenti affermazioni è corretta? E quasi più importante: perché?- c(H2SO4) > c(HSO–4 ) > c(SO2-4 )
- c(HSO–4) > c(H2SO4) > c(SO2-4)
- c(H2SO4) = c(HSO–4) > c(SO2-4)
- c(HSO–4) > c(SO2-4) > c(H2SO4)
- c(SO2-4) > c(HSO–4) > c(H2SO4)
#7617
Soluzione: Il valore di pKs per H2SO4 è -3. Ciò significa in pratica che quasi tutti gli H2SO4 si decompongono in HSO–4 e H+.
Il pKs-valore di 1.92 (quindi circa 2) per HSO–4 dice:, che al momento della iniziazione di (z.B.) 1000 HSO–4 si nel GW circa Un un centesimo (pKs = 2 = -log(0.01) = -log(1/100)) su il pagina del prodotti (quindi SO2-4) si trova, il grandi restante rimane al momento della reagente (: HSO–4).
Il risultato è il seguente:
c(HSO–4) > c(SO2-4) > c(H2SO4)
Solution: - E=h·f = h·c/λ
- Etotal = x·h·f = x·h·c/λ
Etotal est égal à 100 W/s
x est le nombre de particules à 500 nm
x = Etotal · λ / (h·c)
x = 100J·500·10-9 m / (6.026·10-34 Js · 3.0·108m/s)
x = 2.5·1020, soit environ 1/1000 mol
October 16, 2026 at 4:43 am in reply to:Reaction enthalpy Mass difference 2 (thermo-31)On [translation unavailable] (https://de.wikipedia.org/w/index.php?title=%C3%84quivalenzvonMasseundEnergie&oldid=245822194) is of which: applications for the mass conversion according to Einstein, that at the same time, heating to 50 degree centigrade of a [translation unavailable] water (adopted: mass 1 tons of) itself a increase in mass to 2.3 micrograms to be given.
Confirm this value with an invoice.
#9581
Solution: To calculate the mass increase, we must go through the following steps:
→ Calculate the heat energy supplied
→ Calculate mass increase according to Einstein- Q = m·cw·ΔT
- Q = 1000kg · 4,18 kJ/kg · 50 ℃
- Q = 2.09·108 J
- ΔE=Δm·c2 or Δm = ΔE/c2
- Δm = 2.09·108 [kg·m2/s2]/(300'000'000 m/s)2 = 2.32·10-9 kg
October 16, 2026 at 4:43 am in reply to:Frequenza delle particelle (SB-26)Quali sono le particelle presenti in una soluzione idrica di 1 M H2SO4? In quali quantità relative sono presenti?
pKs(H2SO4) sono -3, pks(HSO–4) = 1.92.
Nota: Es si trovano solo le seguenti particelle: H2O, H3O+, HSO–4, SO2-4, (quasi) nessun H2SO4, poiché l'acido solforico è un acido forte
#7615
Soluzione: - Il pKs(H2SO4) = -3, il cioè: quindi, che H2SO4 una molto acido forte è, e quindi quasi a 100% essere il primo (!) H+ trasmette. Ma non rimane (quasi) nessun H2SO4.
x > y > z > c(H2SO4) - Il addizione 1 M H2SO4 dice:, che per litri acqua (=1000 g/M(H2O) = 55 mol) solo un Mol H2SO4 presente è. Quindi l'acqua è chiaramente in eccesso: 55.5 mol H2O + 1 mol H2SO4 –> 54.5 mol H2O + 0 mol H2SO4 + 1 mol H+
c(H2O) > x > y > z > c(H2SO4). Quindi sono ancora aperti c(H3O+), c(HSO–4), c(SO2-4) - Il pks(HSO–4) = 1.92, quindi circa 2 dice:, che al momento della iniziazione di (z.B.) 1000 HSO–4 si nel GW circa Un un centesimo (pKs = 2 = -log(0.01) = -log(1/100)) su il pagina del prodotti (quindi SO2-4) si trova, il grandi restante rimane al momento della reagente (: HSO–4). Esso vale u.a. Quindi:
c(HSO–4) > c(SO2-4) - È ancora aperta la domanda dopo H3O+. Dal primo reazione viene generato almeno un Mol, con ulteriori reazioni successive si formano ulteriori H3O+. Tutte le altre concentrazioni si muovono negli ordini di grandezza sotto un Mol.
- In questo modo si ottiene la seguente sequenza:
c(H2O) > c(H3O+) > c(HSO–4) > c(SO2-4) > H2SO4.
October 16, 2026 at 4:43 am in reply to:Calcul QM 2 (qm-02)Les électrons du vent solaire atteignent la Terre après une durée de vol d'environ 30 heures, où ils peuvent produire des aurores boréales.
Les éclairages verts générés par l'excitation de l'oxygène à λ = 557.7 nm sont prédominants dans les lampes polaires.
Il faut calculer si l'énergie cinétique des électrons du vent solaire est suffisante pour stimuler l'oxygène.
Remarque: la distance entre la Terre et le Soleil est de 150 millions de km
Remarque 2: m(e–)= 9.1·10-31 kg
#5649
Solution: - · Idée générale: l'énergie cinétique doit correspondre au moins à énergie d’excitation
- · Ekin = ½ · m·v2
- = ½ · 9.1·10-31·(1.5·1011m/(30·3600))^2 = 8.8·10-19 J
- · EA = h·c/λ = 6.626·10-34Js·3.0·108/557.7·10-9 = 3.6·10-19 J
- · Ekin / EA = env. 2.4
- C.-à-d. Il est plus moteur de chauffage énergie comme énergie d’excitation présent
October 16, 2026 at 4:43 am in reply to:Reaction enthalpy, mass difference 1 (thermo-30)In the blast gas reaction 2H + O → H2O, the reaction energy of 571.6 kJ/mol is released.
Note: [J] = [kg m2 s-2]
#9579
Solution: - According to Einstein holds E=m·c2 or ΔE=Δm·c2
- c is the speed of light, 300'000 km/s
- Transform the Einstein equation according to m or Δm
- Δm = ΔE/c2
- Δm = 571.6·1000[kg·m2/s2]/(300'000'000 m/s)2 = 6.35·10-12 kg
The calculated 6.35·10-12 kg refers to a Mol. Now, if you want to turn back to a single water molecule, you have to divide it by Avogadro's number (6.022·1023) and you get the theoretical mass reduction per molecule:
6.35·10-12 kg / 6.022·1023 = 1.05·10-35 kgABER: according to 'good question.[translation unavailable]', this time but a useful answer:
The increase at mass through is not through simple supply of energy, but through the DIREKTE conversion of energy to subject matter (the energy KONDENSIERT QUASI ZU MATERIE) this occurring however, at so high temperatures, that the classical physics not more holds. With a pure supply of energy, there is only an increase in temperature.October 16, 2026 at 4:43 am in reply to:Dichiarazioni, quali corrette (SB-25)Esso è una acque, 1 pioggia soluzione una unprotonico forti acido fabbricato ('HX'). Quale delle seguenti affermazioni è corretta. Scusate la scelta.- La acido è dissociata da 0.1%
- L'acido è dissociato all'1%
- L'acido è dissociato al 10%
- L'acido è dissociato al 100%
#7613
Soluzione: La definizione di un acido forte è che l’equilibrio acido si trova completamente sul lato deprotonato:
{HX} -> H^+ + {X}^- {rispettivamente:}{HX} + H2O -> H3O^+ + {X}^-Se quindi nessuno equilibrio presente e le acido completamente decaduto, così parla si anche di una 100% dissociazione. Quindi la soluzione corretta è d .
Solution: a) E = h·c/λ = 6.626·10-34 Js · 299'792'458 m/s / (450·10-9 m) = 4.4114·10-19 J
b) E = n·h·c/λ, n = E·λ/(h·c) = 300J/s · 450·10-9 m / (6.626·10-34 Js · 299792458 m/s) = 6.8·1020October 16, 2026 at 4:43 am in reply to:Calculation of reaction enthalpy 9 (thermo-21)In a poster roll (diameter 6 cm, length 72 cm) a few drops of pentane (1/4 ml) are given and ignited with the air-pentan mixture.
(a) Calculate the reaction enthalpy.
(b) It has been shown experimentally that too much pentane does not produce a better explosion than the air-pentan mixture Calculate the maximum amount of pentane.
Background: wonderful teaching experience.
Note: unknown size – molecules self to erude.
#9577
Solution: Note: [translation unavailable] C5H12, M(C5H12), Dichte(C5H12) = 0.63 g/ml
- Assumptions are as follows:
[translation unavailable] C5H12, M(C5H12) = 72 g/mol
Dichte(C5H12) = 0.626 g/ml
dHf0(C5H12) = -147 kJ/mol
All substances involved are gaseous
Experiment at 25℃ (293 K) - (a) reaction equation:
1·C5H12 (g) + 8·O2 (g) ⇄ 5·CO2(g) + 6·H2O(g) - ΔHoR = ∑ΔHof(Produkte) – ∑ΔHof(Edukte)
ΔHoR = (5· ΔHof(CO2,g) + 6· ΔHof(H2O, g)) – ( ΔHof(C5H12, g) + 8· ΔHof(O2,g))
ΔHoR = (5·-393 + 6·-242) – (-147 + 8·0) = -3270 kJ/mol - actual energy released:
Dichte(C5H12) = 0.626 g/ml
Thus 1/4 ml: 0.15 grams (=0.0021 mol)
E = – 6.81 kJ - (b) Calculation of the maximum amount of pentane
- Volume of the poster roll:
V = pi · r2 · h = 3.141 · 0.032 · 0.72 = 0.00204 m3
V approx. 2 litres - Ideal gas 1 mol at …
0℃ (273 K) 22.4 l
25℃ (298 K): 24 litres
2 litres (volume of poster roll) is 1/12 mol - Air is 20% O2, 80% N2
Thus 1/60 mol O2 in the poster roll
According to the reaction equation 8· less C5H12 than O2, i.e. 1/480 mol C5H12
With M(C5H12) = 72 g/mol followed by 0.15 grams C5H12
With Dichte(C5H12) = 0.63 g/ml following: thus approx. 1/4 ml C5H12
So it releases 6.81 kJ. The maximum amount of pentane is about 1/4 ml.
Solution: Table of values:
ΔHof(kJ·mol-1) So(J·K-1·mol-1) EtOH(l) -277 161 O2 (g) 0 205 CO2 (g) -393 214 H2O (l) -286 67 - reaction equation:
1·C2H5OH + 3·O2 ⇄ 2·CO2(g) + 3·H20(l) - ΔHoR = ∑ΔHof(Produkte) – ∑ΔHof(Edukte)
ΔHoR = (2· ΔHof(CO2,g) + 3· ΔHof(H2O, l)) – ( ΔHof(C2H5OH, l) + 3· ΔHof(O2,g))
ΔHoR = (2·-393 + 3·-286) – (-277 + 3·0) = -1367 kJ/mol (by analogy to the exercise thermo-107)
ΔSoR = (2·So(CO2,g) + 3·So(H2O, l)) – (So(C2H5OH, l) + 3·So(O2,g))
ΔSoR = (2·214 + 3·67) – (161 + 3·205) = -147 J·mol-1·K-1
ΔGoR = ΔHoR – T· ΔSoR
ΔGoR = -1367 – (273+37)·-0.147 = -1321.43 kJ/mol
The results is a not much less exergonically how the similar calculation the exercise 107. Quintessence: the amount of alcohol needed would be about 4% higher.
Solution: Il est valable [traduction manquante] point d’équivalence: n(Base) = n(Säure)
avec c=n/V, on obtient:
c(Base)·V(Base) = c(Säure)·V(Säure)
c(Säure) = c(Base)·V(Base)/V(Säure)
c(Säure) = 0.1M · 30ml / 20 ml = 0.15 M = 0.15 mol/l
Soluzione: Una connessione può numerosi H-atomi contenere, z.B. Acido acido, CH3COOH. Le a il C-atomo legati H's sono meno pesante polarizzata come il H, che a il O-atomo legati è. Ragione: differenze di elettronegatività: C e H hanno valori EN simili e quindi carichi parzialmente positivi o negativi simili. Tuttavia, l'O e l'H presentano valori EN molto diversi, con l'H chiaramente positivamente parzialmente carico, in contrasto con l'O atomo negativamente parzialmente carico. La separazione di un H+ (nota: non una carica parziale, ma una carica positiva completa o l'assenza di un elettrone completamente negativo) è quindi facilitata da questa grande differenza EN. (Nota per gli specialisti: sì, so che HF crea problemi, ma conduce troppo lontano in questo punto)
Soluzione: No. In breve detto: il pH-valore corrisponde (in ultima analisi) una determinati numero protoni, il pKs-valore corrisponde una volontà di versare il protoni. (nota: ciascuno negativi decadici il logaritmo) comparazione: molto i soldi – poco i soldi (:pH), avidità – generosi (:pKs) .
Attenzione (!): Ma matematicamente si può ottenere un'equazione: dall'equazione Henderson-Hasselbalch (pH=pKs + log …) segue puramente matematicamente, se il contributo del valore log è pari a zero, pH = pKsOctober 16, 2026 at 4:43 am in reply to:Calculs du pH, 4 (SB-62)Un litre de deux solutions A et B avec la même pH de départ de 4.8 est indiqué. A est une solution d'acide salé et B une solution d'acide acide.
Maintenant, on ajoute un litre d'eau à chaque solution.- Calculer le nouveau pH de la solution A et B
- La solution à base de laquelle on a une plus grande modification du pH
#5643
Solution: D'après le pH, l'acide HCl pour l'acide fort ainsi que l'acide acide pour l'acide faible peuvent être utilisés. la concentration est calculée:
- acide fort: HCl
pH = -log(c(H3O+)), c(H3O+) = 10-pH = 0.000015 mol/l
C = n/V ou n = c · V
n = 0.000015 · 1.0 l = 0.000015 mol - Acide faible: acide acide
pH = 1/2(pKs-log(HA)), c(HA) = …
n = c·V = - Maintenant, on ajoute 1 litre d'eau pure à chaque solution, et c=n/V donne le résultat suivant:
- HCl: pH = -log(c(H3O+)) = -log(n/V)
pH = il a menti
… Je n' ai pas encore fini !
October 16, 2026 at 4:43 am in reply to:Calculation of reaction enthalpy 7 (thermo-19)Adopted, one decides itself for the not health variation, that the complete daily energy intake by means of drinking of alcohol (40% alcohol) implemented is. The following assumptions and specifications shall apply:- Drinking alcohol would be C2H5OH (ethanol), the density of pure alcohol would be 0.9 g/ml
- Assumption: The alcohol is inhaled in the body, i.e. injected with O2.
- Note 1: Calculate first the reaction enthalpy including state of matter
- Note 2: Calculate from ΔHoR and the amount of ethanol per litre of alcohol the amount needed to realize the energy supply
- Note 3: Daily energy consumption is 9200 kJ
- Note 4: for the professionals: the bases of calculation is not fully, in fact, [translation unavailable] the gibbs free energy of reaction at body temperature calculated are. See details of the following exercise thermo-108. But you can see that the result would only change by about 10 percent.
#9573
Solution: - reaction equation:
1·C2H5OH + 3·O2 ⇄ 2·CO2(g) + 3·H2O(l) - ΔHoR = ∑ΔHof(Produkte) – ∑ΔHof(Edukte)
ΔHoR = (2· ΔHof(CO2(g)) + 3 ΔHof(H2O(l))) – ( ΔHof(C2H5OH) + 3· ΔHof(O2))
ΔHoR = (2·-393 + 3·-286) – (-278 + 3·0) = -1366 kJ/mol
Thus [translation unavailable] one well, you know,, that per Mol [translation unavailable] 1366 kJ released are - Next question: How many grams of ethanol are in alcohol?
1 liter of alcohol, 40%, i.e. 400 ml of pure ethanol. Thus, at a density of 0.9 g/ml, 360 grams of ethanol are produced. - M(C2H5OH) = 46 g/mol, so that
n= m/M = 360 / 46 = 7.8 mol - Thus, 7.8 mol to -1366 kJ per bottle of alcohol is contained, i.e. -10690 kJ.
- So for a daily requirement of 9200 kJ it takes about 860 ml.
October 16, 2026 at 4:43 am in reply to:pH-calculs, des mélanges (SB-61)Calculez le pH des mélanges suivants.- Pour 80 ml d'une solution d'acide salé de 0.05 M, 100 ml d'une solution de sodium de 0.01 M doivent être administrés.
- Pour 60 ml de solution de 0.015 KOH, 30 ml de solution de 0.2 M d'acide salé est administré.
- 10 ml 0.2 M solution de l'acide salé sont tout d'abord dix fois dilué et alors avec
1.0 g Ca(OH)2 déposé.
#5641
Solution: - c=n/V → n=c·V
· 80 ml 0.05 M HCl → n(HCl)=0.004 mol
· 100 ml 0.01 NaOH → n(NaOH)=0.001 mol
· restant à la réaction de neutralisation 0.003 mol HCl
· Note: le volume total est de 80ml + 100 ml
· pH=-log(0.003/0.18) = 1.78 - · 60 ml 0.015 M KOH → n(KOH)=0.0009 mol
· 30 ml 0.2 M HCl → n(HCl)=0.006mol
· Notez que KOH se comporte de la même manière que NaOH, donc c'est aussi une base
· restant à la réaction de neutralisation 0.0051 mol de HCl
· Note: le volume total est de 60ml + 30 ml
· pH=-log(0.0051/0.09) = 1.25 - · Début- pH: pH=-log(0.2) = 0.7
· Une dilution dix fois supérieure à 10 ml signifie une dilution supplémentaire de 90 ml. On donne de l'eau
· 10 ml 0.2 M HCl → n(HCl)=0.002 mol ou 0.002 mol
· n(HCl)=0.002 mol → 0.002 mol H+
· Total le volume de l'appareil: 10ml+90ml=100 ml
· pH=-log(0.002/0.1) = 1.7
· Une augmentation d'une unité de pH fait sens à une dilution de dix fois
· 1 g Ca(OH)2 → n(Ca(OH)2)=1/74.1=0.0135 mol
· n(Ca(OH)2)=0.0135 mol → n(OH–)=2·0.0135= 0.027 mol
· Réaction de neutralisation: 0.002 mol H ainsi que 0.027 mol OH–
· Le reste rester 0.025 mol OH–
· le volume total est de 100 ml
· pOH=-log(0.025/0.1)=0.6 → pH=14-0.6=13.4
Solution: ΔHoR = [ ΔHof(CO(g)) + 3· ΔHof(H2(g))] – [ ΔHof(CH4) + ΔHof(H2O(l))] ΔHoR = 249.5 kJ/mol = [x + 3·0]-[-74.85 + -285.83]
x = …
Soluzione: Se HX è un acido che reagisce con acqua, si può definire con l'aiuto dell'equilibrio chimico: K=(c[H3O+] · c[X–])/(c[H2O · c[HX]) . Del altri può continuare semplificato sono, lì le concentrazione dell'acqua circa 1000 una volta maggiori è nel comparazione a una acido: KS= (c[H3O+] · c[X–])/(c[HX]) . Invece del valore KS si parla anche del valore KW.
Una substanza, quali quindi 'mi piacerebbe' il suo protoni trasmette (a acqua) avrebbe quindi un alti KW-valore e al contrario. Ancora una volta sono le numeri piccole, pertanto è ancora una volta il (denti negativi)-il logaritmo preparazione: pKS = -log(Ks). Quintessenza: il pKS corrisponde il volontà di versare di H+ (protoni) una connessione.October 16, 2026 at 4:43 am in reply to:Calculation of reaction enthalpy 5 (thermo-17)To sweat and cut, you need fuel gas. You usually add ethane (C2H2). Why not the cheaper methane (CH4)?
Note: For both gases, formulate the combustion reaction and determine the reaction enthalpy per (!) molecule C2H2 and CH4 respectively.
ΔHof(CH4) = -75 kJ/mol
ΔHof(C2H2) = 227 kJ/mol
ΔHof(H2O) = -285 kJ/mol
ΔHof(CO2) = -393 kJ/mol
#9569
Solution: - Incineration of ethylene:
1·C2H2(g) + 5/2·O2(g) → 1·H2O(g) + 2·CO2(g)
ΔHoR = ∑ΔHof(Produkte) – ∑ΔHof(Edukte)
ΔHoR = (1·-285+2·-393)-(1·227+5/2·0) = -1298 kJ/mol - Burning of methane:
1·CH4(g) + 2·O2(g) → 2·H2O(g) + 1·CO2(g)
ΔHoR = ∑ΔHof(Produkte) – ∑ΔHof(Edukte)
ΔHoR = (2·-285+1·-393)-(1·-75+2·0) = -880 kJ/mol
The calculation shows that for every turnover of one mol of ethine, about 1.5 times more energy It's released more than methane.
October 16, 2026 at 4:43 am in reply to:Disegnare diversi acidi (SB-15)Disegna le formule di Lewis dei seguenti acidi.{a) Acido acido: }{b) Acido salino:}{c) Acido formico: }{(d) acido solforico: }{(e) Acido salpetrico: }{(e) Acido di carbonio: }
#7605
Soluzione: {a) Acido acido: }H-C<|H><`|H>-C<`|O|>-O-H{b) Acido salino:}H-Cl{c) Acido formico: }H-C<`|O|>-O-H{(d) acido solforico: }H-O-S<`|O^-><|O^->-O-H{(e) Acido salpetrico: }O^-|N^+`/O/\O/H{(e) Acido di carbonio: }HO\C|O`|/OHOctober 16, 2026 at 4:43 am in reply to:Neutralisations (SB-60)Le formulaire les réactions de neutralisation dans type d’écriture et des images les d’autres sels, par exemple: à l’intérieur exercice a).{a) Hydroxyde de sodium + acide salé }Na^+ + OH^- + H3O^+ + Cl^- -> NaCl{(l’accès à l’eau)} + 2H2O{b) Hydroxyde de sodium + acide salphétrique }{(c) Hydroxyde de sodium + acide carbonique }{d) Hydroxyde de potassium + acide sulphurique }{e) Hydroxyde de potassium + acide phosphorique }
#5639
Solution: {a) Hydroxyde de sodium + acide salé }Na^+ + OH^- + H3O^+ + Cl^- -> NaCl{(l’accès à l’eau)} + 2H2O{b) Hydroxyde de sodium + acide salphétrique }Na^+ + OH^- + H3O^+ + NO3^- -> NaNO3{(l’accès à l’eau)} + 2H2O{(c) Hydroxyde de sodium + acide carbonique }2Na^+ + 2OH^- + 2H3O^+ + 2CO3^2- -> Na2CO3{(l’accès à l’eau)} + 4H2O{d) Hydroxyde de potassium + acide sulphurique }2K^+ + 2OH^- + 2H3O^+ + SO4^2- -> K2SO4{(l’accès à l’eau)} + 4H2O{e) Hydroxyde de potassium + acide phosphorique }3K^+ + 3OH^- + 3H3O^+ + PO4^3- -> K3PO4{(l’accès à l’eau)} + 4H2OOctober 16, 2026 at 4:43 am in reply to:Calculation of reaction enthalpy 4 (thermo-16)A cold bag is made up of the following ingredients: 25 g NH4NO3 (ammonium nitrate) and 75 ml of water. Now the ammonium nitrate is dissolved in water.
Note 1: the (specific) heat capacity cw of the water is 75.3_nbspJ/(K·mol) or 4.18 J/(K·kg).
Note 2: Q = m·c·ΔT
Note 3: The ammonium nitrate dissolves in water in its ions, the name indicating which.
#9567
Solution: reaction equation: NH4NO3 → NO–3(aq) + NH+4(aq)
ΔHof(NH4NO3) = -366 kJ/mol
ΔHof(NO–3(aq) = -207 kJ/mol
ΔHof(NH+4(aq)) = -132 kJ/mol- ΔHoR = ∑ΔHof(Produkte) – ∑ΔHof(Edukte)
- ΔHoR = (-207 + -132) – (-366) = + 27 kJ/mol
- [translation unavailable]: per Mol ammonium nitrate are 27 kJ 'consumed', to in solution to going.
- Given were but not a Mol NH4NO3, but only 25 grams. A Mol NH4NO3 corresponding to 80 grams, thus are 8.44 kJ (27·25/80) invested, to the solution to cooling.
- Q = m·c·ΔT is
ΔT = Q/(m·c·) = 8440 J / (0.075 kg · 4180 J/(K·kg)) = + 26.9 K - Since the reaction is endothermic (dHR0 > 0), it cools by 26.9 K (resp. 26.9℃ .
October 16, 2026 at 4:43 am in reply to:Acidi nell’acqua (SB-14)I seguenti acidi sono dissoluti in acqua. Es fabbricazione le accettazione, che le acidi completamente deprotoniare. Scrivere la corrispondente ioni analogamente a esercizio (a).{a) Acido acido: }CH3COOH + H2O <=> CH3COO^- + H3O^+{b) Acido salino:}{c) Acido formico: }{(d) acido solforico: }{(e) Acido salpetrico: }{(e) Acido di carbonio: }
#7603
Soluzione: {a) Acido acido: }CH3COOH + H2O <=> CH3COO^- + H3O^+{b) Acido salino:}HCl + H2O <=> Cl^- + H3O^+{c) Acido formico: }HCOOH + H2O <=> HCOO^- + H3O^+{(d) acido solforico: }H2SO4+ 2H2O <=> SO4^2- + 2H3O^+{(e) Acido salpetrico: }HNO3+ H2O <=> NO3^- + H3O^+{(e) Acido di carbonio: }H2CO3+ 2H2O <=> CO3^2- + 2H3O^+October 16, 2026 at 4:43 am in reply to:pH-calculs, diluctions (SB-49)Calculer les pH des solutions suivantes, le solvant étant toujours de l'eau pure:- Une 0.03 moulés HCl-solution est cent fois dilué.
Calculer le pH avant et après dilution - 20 ml 0.05 M HCl est dilué avec 100 ml d'eau distillée.
Calculer le pH avant et après dilution - À 50 ml une 0.2 molars NaOH-solution est 100 ml destillés eau donné.
Calculer le pH avant et après dilution
#5637
Solution: - Début- pH: pH=-log(0.03) = 1.5
Une dilution de cent fois signifie que 99 parties d'eau sont ajoutées à une solution.
z. B. 1 ml de l'eau 0.03 M solution plus 99 ml
· 1000 ml ≙ 0.03 mol H+
· 1 ml → 0.00003 mol H+
· pH=-log(0.00003/0.001)=1.52
· Notez que 99 ml d'eau sont admises
· pH=-log(0.00003/(0.001+0.099)) = 3.52
Notez que l'augmentation de deux pouvoirs décimaux par rapport aux
H+ La concentration change si elle est de 2 unités au pH - Début- pH: pH=-log(0.05) = 1.3
· 20 ml de 0.05 M de HCl:
· 1000 ml ≙ 0.05 mol H+
· 20 ml → 0.001 mol H+
· Notez que 100 ml d'eau sont admises
· de nouveaux pH: pH=log(n/V)=-log(0.001/(0.02+0.1))= 2.079 - Début- pH: pOH=-log(0.2)=0.7, pH=14-0.7= 13.3
· 1000 ml ≙ 0.2 mol OH–
· 50 ml → 0.01 mol OH–
· Notez que 100 ml d'eau sont admises
· pOH=-log(0.01/(0.05+0.1))=1.18
· pH=14-1.18=12.82
October 16, 2026 at 4:43 am in reply to:Conjugato, diversi esempi 2 (SB-13)Indicare le seguenti reazioni. Ordina le sostanze coinvolte in parti corrispondenti acido – basi{a) } NH3 + HCl <=> NH4^+ + Cl^-{b) } HSO4^- + CN^- <=> HCN + SO4^2-{c) } H3O^+ + HS^- <=> H2S + H2O{d) } N2H4 + HSO4^- <=> N2H5^+ + SO4^2-{e) } H2O + NH2^- <=> NH3 + OH^-
#7601
Soluzione: Nota: le coppie SB coniugate e corrispondenti indicano la stessa situazione
acido 1 base 2 base 1 acido 2 a) NH3 + HCl ⇄ NH+4 + Cl– HCl NH3 Cl– NH+4 b) HSO–4 + CN– ⇄ HCN + SO2-4 HSO–4 CN– SO2-4 HCN c) H3O+ + HS– ⇄ H2S + H2O H3O+ HS– H2O H2S d) N2H4 + HSO–4 ⇄ N2H+5 + SO2-4 HSO–4 N2H4 SO2-4 N2H+5 e) H2O + NH–2 ⇄ NH3 + OH– H2O NH–2 OH– NH3 October 16, 2026 at 4:43 am in reply to:Calculation of reaction enthalpy 3 (thermo-15)Glucose (C6H12O6) can be implemented in different ways: aerobic (with O2) and anaerobic (without O2).
For both reactions, formulate the reaction equation and calculate the standard reaction enthalpy.
Note I: if the ΔHof is unknown, then generally calculate x, y, etc.
Note II: state of matter state
#9565
Solution: ΔHof(C6H12O6) = -1268 kJ/mol
ΔHof(O2)(g) = 0 kJ/mol
ΔHof(C2H5OH)(l) = -278 kJ/mol
ΔHof(H2O)(g) = -286 kJ/mol
ΔHof(CO2) = -393 kJ/mol(a) Combustion reaction:
C6H12O6 + 6·O2(g) ⇄ 6·CO2(g) + 6·H2O(l)
ΔHoR = ∑ΔHof(Produkte) – ∑ΔHof(Edukte)
ΔHoR = (6·-393 + 6·-286)-(-1268+6·0) = – 2806 kJ/mol(b) Fermentation:
C6H12O6 ⇄ 2·C2H5OH(l) + 2·CO2(g)
Note: C2H5OH is called alcohol
ΔHoR = ∑ΔHof(Produkte) – ∑ΔHof(Edukte)
ΔHoR = (2·-278 + 2·-393)-(-1268) = – 74 kJ/molOctober 16, 2026 at 4:43 am in reply to:Calculs du pH, 2 (SB-48)Calculer la masse à H3O+ et OH– en …- a) … un litre d'eau. pH = 6
- b) … dans le lac de Constance. Le pH est de 7
#5635
Solution: Avec pH = -log(c(H3O+)) suivant:: c(H3O+) = 10-pH
La même chose.- Le pH = -log(c(H3O+)) est le suivant:
c(H3O+) = 10-pH ou c(OH–) = 10-pOH
Il en va de même pour c=n/V=m/M/V:
m = c·V·M - a) m(H3O+) = c·V·M=10-6 mol/l · 1.0 l · 19 g/mol = 1.9·10-5 grammes
m(OH–) = 10-8 mol/l · 1.0 l · 17 g/mol = 1.7·10-7 grammes - b) le volume de l'appareil lac de Constance, grossières évaluation: l= 50 km, b= 2km, h=300m
V= 30km3=30·(1000m·1000m·1000m)=109 m3 = 1012 litres
m(H3O+) = c·V·M=10-7 mol/l · 1012 l · 0.019 kg/mol = 1900 kg
m(OH–) = 10-7 mol/l · 1012 l · 0.017 kg/mol = 1700 kg
October 16, 2026 at 4:43 am in reply to:Calculs du pH, 1 (SB-47)Calculer les pH des solutions suivantes, le solvant étant toujours de l'eau pure:- 1 g d'acide salé (HCl) dissous dans un litre d'eau
- 1 kg d'acide salé (HCl) dissous dans un mètre cube d'eau
- 1 g de NaOH, dissous dans 2 litres d'eau
- 81 mg HBr dans 0.1 litre d'eau
- 1 grammes l'acide sulphurique dans 1 m3 eau. Supposons une déprotonation complète de l'acide sulfurique.
#5633
Solution: Remarque 1: Le HCl est un acide fort (pKs < 0), c'est-à-dire qu'il se dissout complètement dans l'eau en H3O+ et en Cl–.
Remarque 2: pH = -log(c(H3O+)) = -log(n/V)
Remarque 3: pH + pOH = 14
Remarque 4: HBr est également un acide fort- a) pH = -log(1/36.5/1) = 1.56
- b) pH = -log(1000/36.5/1000) = 1.56
- c) pOH = -log(1/40/2) = 1.90, pH = 14 – pOH = 12.1
- d) pH = -log(0.081/81/0.1) = 2
- e) L'acide sulfurique, H2SO4 émet deux H+!
pH = -log(2·1/98/1000) = 4.69
October 16, 2026 at 4:43 am in reply to:Calculation of reaction enthalpy 2 (thermo-14)At the turn of 60 grams of grape sugar, x kJ is released. Calculate the ΔHof from this.
#9563
Solution: M(Traubenzucker) = M(C6H12O6) = 180 grams
With 60 g C6H12O6 x kJ, at a Mol (=180 g) thus 3·x.
ΔHof(C6H12O6) = 3·x kJ/mol.AuthorPosts