Explore BrainMass

Physical Chemistry

Standard free energy change for reactions

1. The Standard free energy change for the following reaction is -33.2 kJ/mol and the equilibrium constant Kp=6.59x105 at 25 C. N2(g) + 3H2 (g) <- -> 2NH3 (g) In a certain experiment, the initial pressures are P(H2)=0.25 atm, P(N2)= 0.87 atm and P(NH3)=12.9 atm. Calculate Delta G for the reaction at these pressures and pre

Predicting Reactions and Calculating Quantity

Predict whether the following reaction would proceed spontaneously as written at 298 K by calculating both Delta G and e for the reaction, given that [Co2+] =.15 M and [Fe2+]= 0.68 M. ( E1/2= -0.282 for Co2+ + 2e- -----> Co0) Co0 + Fe2+ ---> Co2+ + Fe0 A current of 0.452 A is passed through an electrolytic cell co

molarity of solution

1. Calculate the molarity of the following solutions from this acid-base titration data: a. If 250 ml of Ba(OH)2 of unknown concentration with a methyl red indicator present is titrated with [0.325 M] HNO3, the yellow solution turns red after 36.4 ml of the HNO3 is added. What is the molarity of the Ba(OH)2 solution? b.

Chemistry Help

1. How many grams of CO2 would be formed from 20 grams of C8H10 in the following (UNBALANCED) reaction? C8H10 + O2 --> CO2 + H2O 2. How many moles of CO2 would be formed from 40 grams of CaCO3 in the following (UNBALANCED) equation? CaCO3 + HCl --> CaCl2 + CO2 + H2O 3. A gas sample has an original volume of 700 ml when

Analytical Chemistry Calculations

6. A solution of Al2S3 is converted, by chemical means, to a form which can be precipitated as BaSO4. Calculate the gravimetric factor which allows determining BaSO4 from a sample of Al2S3. 7. What pH is required to just precipitate iron (III) hydroxide from a 0.10 M FeCl3 solution? Ksp for FE(OH)3 is 4 x 10^-38. 8. Calcul

Calculate the molar mass of geraniol

See attached file for full problem description. 1. The volatile organic compound geraniol, a component of oil of roses, is used in perfumery. It was found that the density of the vapor at 260ºC is 0.480 g/L when the pressure is 103 Torr. Calculate the molar mass of geraniol. 2. consider the following apparatus. Calculat

Isopentane Questions

(a) The molar volume of isopentane (C5H12) is 1.00 L at 503 K and 30.0 atm. (i) Does isopentane behave like an ideal gas? Justify your answer. (ii) Given that a = 17.0 L^2.atm/mol2 and b = 0.136L/mol calculate the pressure of isopentane as predicted by the van der waals equation. (b) The elements of group 5A, the nitro

Heat Engine, Net Work, Waste Heat

An inventor claims to have developed a heat engine that receives 750 kJ of heat from a source at 400K and produces 250 kJ of net work while rejecting the waste heat to a sink at 300K. Is this a reasonable claim? Why?

Titration of a Strong Acid

Procedure 1 (click to view assignments for this procedure) PLEASE NOTE: Titration requires several steps in order to obtain exact results. 1. Take a clean Erlenmeyer flask from the Glassware shelf and place it on the workbench. 2. Add 25 mL HCl (of unknown concentration) to the flask. 3. Add 2 drops of phenolphthal

Solutions, Solubility and Concentration

18. The chloride in a 0.12-g sample of 95% pure MgCl2 is to be precipitated... Solutions, Solubility and Concentration. See attached file for full problem description.

acid base titration.

See attached file for full problem description. 13. A hydrocholoric acid solution is standardinzed by titrating 0.4541 g of primary stardard tris(hydroxymethyl)aminomethane. If 35.37 mL is required for the titration, what is the molarity of the acid? 15. A sodium hydroxide solution is standardized by titrating 0.8592 g of

Balanced & Net Ionic Equations

Write the balanced molecular equation, complete ionic and net ionic equation for the following acid base reaction. HCL(aq) + NH3(aq) NH3 is an exception, so I'm not sure what to do with it.

Combustion and Metal Reactions

14. The gaseous hydrocarbon acetylene, C2H2, is used in welders' torches because of the large amount of heat released when acetylene burns with oxygen, producing carbon dioxide and water. First, write a balanced equation for the combustion of acetylene in oxygen. Then, how many grams of acetylene are needed for the complete comb

Salts and Their Reactions

7. When 1.00 grams of chromium metal is heated in excess iodine, 8.301 rams of chromium iodide salt is formed. Calculate the empirical formula of this salt. 8. When a calcium carbonate tablet is ingested, it dissolves by the reaction of stomach acid, which contains hydrochloric acid. The unbalanced equation for this reaction

Find how many grams of oxygen

1. In the following problem, first find how many grams of oxygen would be used to completely react with 230 grams of pentyl alcohol (C5H11OH)? How many grams of oxygen would be used? See attached file for full problem description.

Percent manganese in a sample

A 0.500g sample is analyzed spectrophotometrically for manganese by dissolving it in acid and transferring to a 250mL flask and diluting to volume. Three aliquots are analyzed by transforming 50mL portions with a pipet to 500mL Erlenmeyer flasks and reacting with an oxidizing agent, potassium peroxydisulfate, to convert the mang

Analysis of Calcite Sample

The analysis of a calcite sample yielded CaO percentages of 55.95, 56.00, 56.04, 56.08, and 56.23, respectively. The last value appears anomalous; should it be retained or rejected?

PH, pOH, PKw Calculations

Calculating pH, POH, PKa, PKb. 59) Calculate the hydrogen ion concentration for a 0.0200 M solution of HCN in 0100 M NaCl.

PH, pOH, PKw

Calculating pH, POH, PKa, PKb. 37) PH 0.600 M solution of Na2S Sodium sulfide is a salt of a weak acid (hydrogen sulfide) and a strong alkali (sodium hydroxide). It therefore undergoes hydrolysis in water. Na2S = 2Na+ + S2- S2- + 2H2O = H2S + 2OH- Kh = [H2S][OH-] [S2-] [OH-] = Kh[S2-] [H2S] PO