Explore BrainMass

Physical Chemistry

Buffers, Acids, Bases, Salts, Ka and Kb

QUESTION 1 Imagine that you are in chemistry lab and need to make 1.00L of a solution with a pH of 2.50. You have in front of you: - 100mL of 7.00x10-2 M HCl - 100mL of 5.00x10-2 M NaOH, and - Plenty of distilled water. You start to add HCl to a beaker of water when someone asks you a question. When you return t

Mass and Moles of Elements

To do this assignment, use your calculator to do the calculations required. Then invert the calculator to read the message word. Insert the message word into the appropriate space in the statement. Round off all atomic masses to the nearest whole number before using them. When handing in your assignment, be sure to show all

Using Equilibrium to Calculate Product

At low to moderate pressures, the equilibrium state of the water gas shift CO (g) + H2O (g) CO2 (g) + H2 (g) reaction is approximately described by the relation kp = (see attached file) The feed to a continuous shift reactor contains 30 mol% CO, 10 mol% CO2, 40 mol% water and the balance an inert gas. Th

Confirmatory Experiments : Freezing Point Depression and Solubility Tests

The purpose of lab this week is to do "comfirmatory experiments" that further explore the properties of your unknown compound and confirm that it reacts appropriately for the compound you predicted it to be at the end of lab last week. 1. Suppose your unknown is sodium acetate. When a solution of calcium chloride is adde

Heat Created by the Fermentation and Combustion of Glucose

Please help with the following physical chemistry problem: Alcoholic fermentation by microorganisms involves the breakdown of glucose into ethanol and carbon dioxide. C6H12O6 (s) -->; 2 C2H5OH (l) + 2 CO2 (g) a) Calculate the amount of heat liberated in a yeast brew upon fermentation of 1 mol of glucose at 25 °C and 1

Titration and Molarity Questions

Part A. Standardization of the 0.02 M KMnO4 solution with Fe(NH4)2(SO4)2 ? 6H2O. (Molecular weight of the ferrous sulfate hexahydrate is 392.16 g/mol). If you weigh out 1.01 g of the Fe(NH4)2(SO4)2 ? 6H2O, how many moles of iron (Fe+2) are in the sample? Part B Assume you fill a buret with your KMnO4 solution and the v

Meaning, use and calculation of empirical formulas

In this introduction are given the explanation of how to find out an empirical formula if one has found out the chemical elements of an unknown substance and measured their ratio of masses. Also, it is described how one can calculate the ratio of masses from a given empirical formula. Two examples and the explanation of the pri

Molar Concentration of Copper (II) Nitrate

Please help with the following problem. Provide step by step calculations in this answer. A 25.00 mL sample containing Cu2+ gave an instrument signal of 23.6 units (corrected for a blank). When exactly 0.500 mL of 0.0287 M Cu(NO3)2 was added to this solution, the signal increased to 37.9 units. Calculate the molar concentrat

Heat Required to Convert Solid Benzene

The molar heat capacity of C6H6(l) is 136 J/mol x degrees centigrade and of C6H6 (g) is 81.6 J/mol x degrees centigrade. The molar heat of fusion for benzene is 9.92 kJ/mol and its molar heat of vaporization is 30.8 kJ/mole. The melting point of benzene is 5.5 degrees centigrade, its boiling point is 80.1 degrees centigrade and

pH and molar concentration of hydrogen ion

1.Given the molar concentration of hydrogen ion [H+] = 6.2 x 10 -7, calculate the concentration of hydroxide ion. 2.Given the molar concentration of hydroxide ion [OH -] = 4.6 X 10 -13, calculate the concentration of hydrogen ion. 3. In 1 mL of water there are 3 X 1022 molecules of H2O. How many hydrogen ions are in 1 mL o

Empirical Formulation of a Compound

16. A compound contains 40.00% carbon, 6.67% hydrogen, and 53.33% oxygen. Determine the empirical formula of the compound. Please help with the following problems. 1. Give the chemical formula for calcium phosphate. 2. A hypothetical element, Js, has three naturally occurring isotopes. The atomic mass and relative abunda

Gasoline in a tank. To determine pressure etc.

The gasoline storage tank is filled to 12m and the closed space above is filled with nitrogen gas N2. For the condiction shown (see attachment) determine : a) Pressure of nitrogen gas b) Density of gasoline c) Force on the tank bottom d) Force on the flat door e) Minimum force to hold door closed

Energy Changes Due to Pressure and Temperature Changes

1. a volume of 20 cu ft of air at pressure of 50 psig is heated and expanded to 30 cu ft and 40psig find the change in the energy of air in joules. (A)35564 j (B) 48219 j (C)123378 j (d)167278j 2>A quantity of gas equal to 35 cu ft is to be expanded adiabatically.It has specific heat at constant pressure of 0.532 and

Expansion of Nitrogen - Ideal Gas Law

A sample of nitrogen gas has a volume of 3.00 L at 25 degrees C. What volume will it occupy at each of the following temperatures if the pressure and number of moles are constant: a) 546K b) 273K c) 373K

Acid-base titration & analytical chemistry

A 0.213-g sample of uranyl(VI)nitrate, UO2(NO3)2, is dissolved in 20.0 mL of 1.0 M H2SO4 and shaken with Zn. The zinc reduces the uranyl ion, UO2 (with a charge of 2+), to a uranium ion, Un+ (where n+ is the charge of the uranium ion). To determine the value of n, this solution is titrated with KMnO4. Permanganate is reduced to

Which is an acid according to Lewis, but not according to Bronsted?

Please see the attached file. 2. Balance this equation using no fractional coefficients H2O + CrO4^2- + HSnO2- ---> HSNO3- + CrO2- + OH- 3. Balance this equation using no fractional coefficients MnO4- + H2O2 + H+ --> Mn2+ + O2 + H2O 4. Which is an acid according to Lewis, but not according to Bronsted? OH- O2- CO2

Pressure of dry butane gas

I am working on a Chemistry lab write up and I have to determine the pressure of the dry butane gas. My Data Table: initial mass of lighter= 21.03g volume of gas collected= 93.6 mL temperature of the water= 23.2 degrees C barometric pressure= 1.012 atm final mass of lighter= 20.820 therefore the mass of butane collec

Positive or Negative Electrolyte Charging

If you have an electrolyte solution in which you have inserted an electrode to charge it either positive or negative - and then you remove the electrode - is it possible to then magnetize this solution by any one or several methods?

Typical Concentration Problems

22. How many grams of potassium permanganate, KMnO4, are required to make 2.00X10^2cm^3of a 1.50M solution? 27. What is the concentration of a solution that contains 90.3g of MgSO4 in 5.00 x10^2cm^3?

Equilibrium - I.C.E. Question

Phosgene, COCl2 (g), is an extremely toxic gas. It was used during World War I. Today it is used to manufacture pesticides, pharmaceuticals, dyes, and polymers. It is prepared by mixing carbon monoxide and chlorine gas. CO (g) + Cl2 (g) = COCl2 (g) <-- the equal sign should be the sign for foward and reversible

Physical Chemistry Questions

1) How many milliliters of 0.480M NaOH would be required to titrate a 5.00ml solution of 0.320M H2SO4? Report answer to the correct number of significant figures. 2) Write a balanced equation for the combustion of octane, C8H18. 3) If the standard enthalpy of formation (deltaHf) of methanol, CH3OH, is -238.6kJ/mol, deltaHf(CO

Gaussian Plume-Qualitative

Explain qualitatively how the following would change the calculated surface concentration of SO2 assuming a gaussian plume from a smoke stack that follows the gaussian equation for the concentration of SO2 i) The wind speed decreased. ii) The wind speed increased. iii) A stable temperature profile became unstable. iv) An

Liquid Phase Oxidation of S(IV) to S(VI) and pH Lowering

Write the reactions responsible for the LIQUID PHASE oxidation of S(IV) to S(VI), and show how the oxidation can lead to a decrease in pH of rain water. I think you can help me with this. Please let me know. I've included all details.Thank you Dr. M. There are two sets of reactions with 3 parts for each set. I'm not sure w

Colligative Properties/Phase Diagrams/Intermolecular Forces

Diagram and explain the H-Bonds if they exist for the following molecules: (a.)H2S, (b.)CH4, (c.)H2SO3, and (d) PH3. Give reasons for the fact that ionic solids as NaCl have high melting points and dissolve readily in water, whereas network solids such as diamond have very high melting points and do not dissolve in water.