an experiment was preformed under identical conditions as yours. The absorbance of the penny solution was recorded as 0.231 absorbance units. A calibration plot of absorbance vs concentration of cu(II) (mM) yielded the following trendily equations y= 11591x +.50
a. What is the concentration of the original penny solution?
b. How many grams of Cu are in this solution?
c. if the percent Cu was determined to be 2.70 percent what was the mass of the penny?
In: Chemistry
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.
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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