a rock returned from the surface of the moon has a ratio of Rb87 to stable Sr87 atomos equal to 14.45 assuming that this was all Rb87 upon the formation of the solar system, estimate the age of the solar system.
ans key:
t= 4.537*109 yr
In: Chemistry
11. If 0.0296 L of stock solution are diluted to 3.00L to form 0.345 M solution, what is the concentration of the stock solution?
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56.0 mL of 2.50 M Fe(NO3)2 is combined with 25.0 mL of 0.0525 M Na2CO3.
Ksp of FeCO3 is 2.1 × 10-11.
What mass of FeCO3(s) will be produced? in grams
What is the [Fe2+] in the solution final solution? in M
What is the [CO32-] in the solution final solution? in M
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An alkane with the formula C6H14 can be prepared by hydrogenation of either of only two precursor alkenes having the formula C6H12. Write the structure of this alkane, give its IUPAC name, and show the reactions. My confusion is to why the answer is not simply 2,3-hexene and the alkane is not hexane.
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Find the temperature in ºC at which Kp = 43.7 for the reaction H2(g) + I2(g) ⇌ 2 HI(g). Use ∆Hºrxn and ∆Sºrxn to calculate and assume that they are independent of temperature. Use the thermodynamic data in the appendix of your textbook; I have provided the needed appendix on BlackBoard for your convenience. Report your answer to zero places past the decimal.
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Nuclear Binding Energy
a)Calculate the mass defect of the helium nucleus 52He. The mass of neutral 52He is given by MHe=5.012225amu. Express your answer in atomic mass units to four significant figures.
b)Calculate the binding energy E of the helium nucleus 52He (1eV=1.602×10−19J). Express your answer in millions of electron volts to four significant figures.
c)Calculate the binding energy per nucleon of the helium nucleus 52He. Express your answer in millions of electron volts to four significant figures.
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Using a molecular mechanics program, calculate the energy difference or the difference in heats of formation between Z- and E-stilbene. How do your computed values compare to the difference in heats of hydrogenation of the two isomers.
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How is Avogadro's principle (n1/v1=n2/v2) derived from the ideal gas law. Can you show me the algebraic steps?
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If hydrogen sulfide concentrations are greater than 0.15 mg S/L, it is harmful to fish health, calculate the minimum safe pH, if the total sulfide concentration is determined to be 20 micrometers. Assume this is a closed system and there is no H2S transfer with the atmosphere. pKa1= 7, pKa2= 12 for H2S. Molar mass for sulfur is 32g/mol
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Describe the influences and forces driving the formation of the lipid bilayer. Briefly discuss the effect of a phase transition on a lipid bilayer
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A reaction has and △H°298 = 151 kJ/mol and △S°298 = 286 J /mol K at 298 K. Calculate △G in kJ/mol.
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A major organic acid in this juice is malic acid, a dicarboxylic acid with molecular weight of 134. You are asked to determine the total acidity of this juice and a 10-mL portion of this juice took 8.5 mL of 0.105 N NaOH to neutralize to the phenolphthalein endpoint. What is the acidity in mg malic acid/mL juice unit and in % (weight) unit?
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Calculate the pH for each case in the titration of 50.0 mL of 0.240 M HClO(aq)0.240 M HClO(aq) with 0.240 M KOH(aq). Use the ionization constant for HClO.
What is the pH before addition of any KOH?
What is the pH after addition of 25.0 mL KOH?
What is the pH after addition of 30.0 mL KOH?
What is the pH after addition of 50.0 mL KOH?
What is the pH after addition of 60.0 mL KOH?
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A 25.0 mL sample of 0.150 M potassium hydroxide is titrated with 0.125 M hydrobromic acid solution. Calculate the pH after the following volumes of acid have been added: a) 20.0 mL b) 25.0 mL c) 30.0 mL d) 35.0 mL e) 40.0 mL
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Would you have affected the freezing point of water as much as you affected the freezing point of benzene? Explain using the Df for each solvent as part of your explanation.
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