Hi, I have some questions about the concepts of energy in chemistry.
#1 A particular chemical reaction has a negative deltaH and a
negative deltaS. Which statement is correct?
The answer:
-The reaction becomes spontaneous as temperature decreases.
Can someone please explain to me how this is true?
#2 For the process O2(g)---> 2O(g), deltaH = +498kJ. What would
be predicted for the sign of deltaS(rxn) and the conditions under
which this reaction would be spontaneous?
The answer:
deltaS(rxn)=positive & spontaneous at low temperatures
only.
Can someone please elaborate on this?
#3 For which reaction, carried out at standard conditions, would
both the enthalpy and entropy changes drive the reaction in the
same direction?
Answer:
N2(g) + 2O2(g) ---> 2NO2(g) deltaH=+67.7
Why?
In: Chemistry
Determine the ground electronic state of the BeC molecule. Explain your answer.
The answer requires the molecular orbital diagram as well as an electron configuration.
In: Chemistry
What is the maximum number of grams of Iron (III) sulfide, Fe2S3, which can be obtained from the reaction of 80.0g of Fe and 78.0g of S?
(FW Fe=55.85, S=32.07, Fe2S3=207.91) Please show work
In: Chemistry
When you add 2.0ml of 0.50 M S2O32- to the 2.0 ml of 0.10M silver nitrate, formation of Ag(S2O3)23- occured by equation Ag+ +2S2O32- <---->Ag(S2O3)23- Ecell increased even though formation of a solid was not observed.
a) Using the value Ecell = 0.70V, calculate the [Ag+] in the test solution after equilibrium is reached.
b). Setup a reaction table for equation above and calculate the formation constant for Ag(S2O3)23- .
Show your calculations clearly.
In: Chemistry
1- Spectrophotometric determination of copper. was this experiment quantitative?
2- Briefly, what is the purpose of the blank measurement (when the cuvette was filled with water)?
In: Chemistry
The enthalpy of fusion for benzene is 127.34 kJ/kg, and its melting point is 5.49 Celcius. Estimate deltaG when 1.00 mole of benzene melts at 25 Celsius.
The optionns are:
A. 8.312kJ
B. -0.696kJ
C. 35.661 kJ
D. -11.301 kJ
In: Chemistry
I will rate, please answer.
acetone and toulene are both volatile liquids. At 25 C , the vapor pressure of pure acetone and pure otulene are 35.2 torr and 77.9 torr, respectively.
a) Sketch a Raoult's Law plot for this 2 component solution, assuming ideal behavior, and calculate the vapor pressure above a solution containing 0.767 mole of acetone and 0.553 mole of toulene
b) The vapor pressure of the above oslution (in a) was experimentally measured and was found tob e 62.8 torr. Exokain the significance of the experimental results and explain whether the sign of the delta H of the solution is + or -.
In: Chemistry
Calculate the concentration of all species in a 0.19 M KF solution.
Please dont do it wrong its been wrong all over the internet and it makes no sense
In: Chemistry
The following question is offered in anticipation of our chapters on metabolism: Assuming that the average weight of an adult is 154 lbs, how many molecules arrive each second at a mitochondrion of an average active person? Assume that oxygen consumption is 49 mL per minute per kilogram of body weight, adults have about 1 × 1012 cells, and there are 800. mitochondria per cell. Assume that one pound equals 0.454 kg, and that oxygen gas occupies 22.4 L per mol. Report your answer to the nearest ones.
In: Chemistry
Which of the following parameters would be different for a reaction carried out in the presence of a catalyst, compared with the same reaction carried out in the absence of a catalyst?
ΔG∘, ΔH‡, Ea, ΔS‡, ΔH∘, Keq, ΔG‡, ΔS∘, k
In: Chemistry
A copper, Cu(s), electrode is immersed in a solution that is
1.00 M in ammonia, NH3, and 1.00 M in tetraamminecopper(II),
[Cu(NH3)4]^{2+}. If a standard hydrogen electrode is used as the
cathode, the cell potential, Ecell, is found to be 0.075 V at 298
K.
Half reaction of Cu = .337 V
Half reaction of H = .000 V
Based on the cell potential, what is the concentration of Cu^{2+}
in this solution?
[Cu2+]____ with units
PLEASE HELP ME!!
In: Chemistry
100 mL of a river water sample took 9.30 mL of 0.01005 M Ag+ to titrate. Calculate the concentration of Cl- in ppm (μg/mL or mg/L) for the river water.
In: Chemistry
Complete the following acid-base reaction with balanced molecular, total ioic, and net ionic equations. calcium hydroxide(aq) + acetic acid(aq) =
Molecular:
Total ionic: Reactants
Products
Net Ionic:
In: Chemistry
In: Chemistry
Please explain the science behind fuel alternatives; biodiesel, ethanol and MTBE.
In: Chemistry