Explore BrainMass

Physical Chemistry

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

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

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

empirical formula and molecular formula

2) Two substances Q and R each have the elemental composition C = 60% h=13.3% 0=26.7% by mass 0.60 grams of each substance occupied a volume of 0.336 liters at 137 Celcius and standard pressure a) Calculate the empirical formula and the relative molecular mass of Q and R. B) What is the molecular formula

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?

ICE Problem: Calculate Final Concentrations

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 forward and reversible re

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

Rate of S(IV) to S(VI) at Different pHs using O3 and H2O2

If the ozone concentration in the plume is 80 ppb, calculate the liquid-phase rate of S(IV) oxidation in the plume by ozone. The rate for the oxidation of SO2 by H2O2 is given by the expression: please see attachment for expression. where k = 7.45 &#61620; 107 M-2 s-1 and K = 13 M-1. If the pH of the rainwater is 4.3, ca

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

Maximum buffer capacity: Example problem

The question is attached. Starting with equation (8.5) show that the maximum buffer capacity occur at pH=pKa. The units of buffer capacity are mol L^-1. As a consequence of the definitions, buffer capacity is always a positive quantity. For a monoprotic acid the buffer capacity (as a function of pH) is given by: (see attach

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.

Problem involving calculating Pressure

1. If a pressure reading is 20 psi, what is the pressure in foot of water? 2. What is the pressure in psi for a pressure head of 46.2 feet? 3. What is the pressure in psi for a pressure reading, in psi, at the bottom of a 30 feet high reservoir, which has a diameter of 50 feet? 4. What is the pressure in psi of th

Combustion of Sucrose in a Bomb Calorimeter

1. Combustion of 2.016 grams of solid sucrose (C6H12O6) at 25 º C in a bomb calorimeter with heat capacity 9550 J K -1 gives a temperature rise of 3.282 º C. a) Write the balanced equation for the combustion of sucrose b) What is the work done by the system? c) What is the heat change per mole of sucrose for the reaction?

Kinetic Molecular Theory of Gases Questions

1. Calculate the average kinetic energy of the N2 molecules in a sample of N2 gas at 273K and at 546K. 2. Consider separate 1.0 L gaseous samples of H2, Xe, Cl2 and O2 at STP. a) Rank gases in increasing kinetic energy. b) Rank gases in increasing velocity. c) How can separate 1.0 L samples of H2 and O2 have the same aver

Pressure and Temperature Determination

Suggest the pressure and temperature at which 1.0 mol of (a) Nh3, (b) Xe, (c) He will be in states that correspond to 1.0 mol of H2 at 1.0 atm and 25 degrees Celsius. NH3: T = 3.64 x 10^3 K, p= 8.7 atm, Xe: T=2.60K, p=4.5 atm, He: T=46.7K, p=0.18 atm.

equation of gas state leading to critical behavior

Please see attached file. A scientist proposted the following equation of state P = RT/Vm -B/Vm^2 + C/Vm^3 where B and C are independent of the temperatures. Show that the equation leads to critical behavior. Find the critical constants of the gas in terms of B and C and expression for the critical compression factor

Equilibrium Expression of a Buffer

If you add Na2CO3 with NaHCO3 and distilled water what is the equilibrium expression for the buffer? And what is the weak buffer and the conjugate base? What Ions are present in the solution?

DeltaG Values from Reactions and Non-standard Conditions

1) If the overall deltaG of the following reaction is -5.3Kcal/M and we know that the deltaG for the conversion of ADP + Pi ---> ATP is +7.3Kcal/M, what must the deltaG be for the conversion of PEP ----> pyruvate? Phosphoenolpyruvate (PEP) + ADP ----> pyruvate + ATP 2) Working in the lab, you determine the deltaG0 for t

The Initial Rate of Acetylaldehyde

1. The initial rate of acetylaldehyde, CH3CHO at 600ºC is CH&#8595;3CHO(g) → CH↓4(g) + CO(g) Was measured at a series of concentrations with the following results: [CH3CHO] 0.10M 0.20M 0.30M 0.40M Rate(mol/L?s) 0.085 0.34 0.76 1.4 Using these data, determine the reaction order; that is, determine the value of m