Nun im Themenbereich Thermodynamik_en
Topic ThermodynamicsAll problems and solutions as
pdf here.Learning objectives resp. question areas:
- Ab thermo-01 : Joule
- Ab thermo-10 : enthalpy - entropy
- Ab thermo-30 : Einstein, loss of mass
- Ab thermo-40 : Gibbs, settling points
- This forum has 24 topics, 24 replies, and was last updated 4 days, 22 hours ago by .
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- Joule, uses 0 (thermo-01)Suppose you had 1 joule at your disposal. What can be done with it?
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- 4 days, 22 hours ago
- Joule, uses 1 (thermo-02)Suppose you had 1 kJ (1000 joules) at your disposal.
- How many degrees Celsius can a liter of water be heated with it?
Note: to 1 grams water to 1 degree centigrade to heating, required one about 4.18 [translation unavailable]. - How long does a light bulb with 100 watts burn?
- Which mass can be accelerated from 0 m/s to 1 m/s. Ekin = ½ · m · v2
- How many heartbeats or how long can the heart beat? Assuming the power of the heart is 1 watt.
- In the event of a subsequent exercise ('pentane explosion') 6.8 kJ are released. How many feet could a chemistry teacher be lifted with this energy?
- How many degrees Celsius can a liter of water be heated with it?
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- 4 days, 22 hours ago
- Joule, uses 2 (thermo-03)To climb the Eiffel Tower, you have to spend energy that can be fed to your body through food, so how many rubber bears do you have to eat to compensate for the energy needed to climb the Eiffel Tower?
Note: Unknown sizes should be checked on their own. - 1
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- 4 days, 22 hours ago
- Joule, uses 3 (thermo-04)
- How many [translation unavailable] heat are produced, where: a 1000 kg heavy car from the 95 km/h fully braking is?
- How much kg water could one of 10℃ on 60℃ with the amount of energy the previously exercise heating?
- A drop of water falls out of a cloud.
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- 4 days, 22 hours ago
- Joule, mixed, 1 (thermo-05)You mix 1 kg of melting ice and 1 kg of sitting ice. What is the temperature of the mixture when all the ice has melted?
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- 4 days, 22 hours ago
- Joule, lower heating value (thermo-06)Determine the lower heating value of brennsprit ('Spiritus') from the following information: 500 grams of water are heated by 1 grams of brennsprit from 20.4℃ to 22.7℃
Note: the lower heating value H is in [translation unavailable] (or kJ) per kg indicated - 1
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- 4 days, 22 hours ago
- Joule, lower heating value, hazelnut (thermo-07)The following experiment: a hazelnut warms up water in a glass jar. Give a equation at, wherein the in the nuts 'stored' higher heating value submitted is.
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- 4 days, 22 hours ago
- Calculation of reaction enthalpy (thermo-10)How is the reaction enthalpy of any reaction calculated?
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- 4 days, 22 hours ago
- Reaction enthalpy or reaction trope (thermo-11)Think about it to you for each the following operations, whether or not each a increase or a decrease the entropy and the enthalpy of the chemical products [translation unavailable] to expected is (z.B. ΔHoR of which:0 and so on.):
- CO2(s) sublimated to CO2(g)
- Heating by CaCO3(s)
- CO2(g) + CaO(s) → CaCO3(s)
- H2O(s) → H2O(l) → H2O(g) → 0.5·O2(g) + H2(g)
- Ba(OH)2(s) + 2·NH4SCN(s) → Ba(SCN)2 + 2·NH3(g) + 2·H2O(l)
- NH3(g) + HCl(g) → NH4Cl(s)
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- 4 days, 22 hours ago
- Comparing entropy 2 (thermo-12)Given be the molecule C2H6 and CH4. Which this both connections is shown a higher entropy on. Reason your choice.
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- 4 days, 22 hours ago
- Calculation of reaction enthalpy 1 (thermo-13)Calculate the standardized-reaction enthalpy following reaction:
H2(g) + 1/8 S8 (s) ⇄ H2S(g) - 1
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- 4 days, 22 hours ago
- 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.
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- 4 days, 22 hours ago
- 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 - 1
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- 4 days, 22 hours ago
- 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. - 1
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- 4 days, 22 hours ago
- 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 - 1
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- 4 days, 22 hours ago
- Calculation of reaction enthalpy 6 (thermo-18)Calculate the ΔHof of carbon monoxide and consider the following reaction:
CH4(g) + H2O(l) → CO(g) + 3 H2(g). The (experimental) ΔHoR for this purpose of which: 249.5 kJ/mol. - 1
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- 4 days, 22 hours ago
- 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.
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- 4 days, 22 hours ago
- Calculation of reaction enthalpy 8 (thermo-20)Analogs exercise to thermo-18. It should but only the gibbs free energy of reaction at body temperature for the air conditioning (incineration) of [translation unavailable] calculated are.
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- 4 days, 22 hours ago
- 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. - 1
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- 4 days, 22 hours ago
- 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] - 1
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- 4 days, 22 hours ago
- 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. - 1
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- 4 days, 22 hours ago
- 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.
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- Calculate seed temperature (thermo-41)Calculate the boiling point of the water .
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- 4 days, 22 hours ago
- 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. - 1
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