Explore BrainMass

Physical Chemistry

Understanding Vapour Pressure

Which would you expect to exhibit the highest vapor pressure at room temperature? - Helium(Delta H fusion 0.02, Delta H vaporization 0.10) - Benzene(Delta H fusion 9.95, Delta H vaporization 30.8) - Water(Delta H fusion 6.01, Delta H vaporization 40.67) - Mercury(Delta H fusion 2.33, Delta H vaporization 56.9)

Solution Concentrations

Find the concentration of 500mg of alltrans retinol 0.1% per 1 ounce of solution. Vitamin A C20H30O F.W. 286.46 CAS 68-26-8 Ratings Health: 1 Flammability: 1 Reactivity: 0 Chemical Specifications: Assay Min. 99% Storage Information: LIGHT SENSITIVE, REFRIGERATE: Keep tightly clos

Heating and Cooling Chemical Reactions

Why when heating and cooling three different separate substances in open containers does the mass change in two of them (one loss mass; the other gained mass) but stays the same in the third when it is known that mass is conserved in chemical reactions? Would it be because one gave off vapor, the second melted and the third was

Gibbs-Duhem Equation

In a certain binary solution, the activity of component 1 is given by R * ln(alpha_1) = R * ln(x_1) + A(x_2)^2 + B(x_2)^3 Where x_1 and x_2 are the respective mole fractions and A and B are constants. Derive an expression for alpha_2 (the activity of component 2) given that the equation above is valid over the entire conc

Semi-Empirical Expression for a Dilute Real Solution

Starting with the definition of osmotic pressure Pi = -RT/V_ml * ln * (p_so*ln)/(p_1)^0 Derive the semi-empirical expression for a dilute real solution Pi/C' = RT/M_2 + bC' Where C' is the concentration expressed in (g solute)/(dm3 solution) and b is known as the interaction constant. Then use the semiempirical formu

Fugacity from Bethelot equation

Carbon dioxide obeys the reduced Bethelot equation reasonably well (i have attached the equation) Given Tc = 304.3K and Pc = 73.0 atm, calculate the fugacity of carbon dioxide at 150 degrees C and 50 atm.

Ideal gas law? free energy of mixing ...

I think the ideal gas law does not apply in this following problem because this problem is addressing a liquid. then how do i think through and do this problem? Calculate the free energy of mixing when 1 mole of liquid A is mixed with 4 moles of liquid B at 25 degrees C to form an ideal solution. What is the change in chemic

Standard Temperature Pressure and Volume

1. The respiratory rate of a person is 20 breathes per minute. If every average breath is about 310cm^3 of air at 22C and 740mmHG, what volume of air in cubic meters and corrected to standard temperature and pressure conditions does a person breathe in one day?

Perfect (ideal) gases (4 part question)

Suppose your balloon has a radius of 3 m and that it is a spere when inflated. a.) how much H is needed to inflate it to a pressure of 1 atm at an ambient T of 25 celsius @ sea level? b.) what mass can the balloon lift @sea level, where the density of air is 1.22 kg m^-3 ? c.) what would be the payload if helium were used ins

Calculating Kc

Given the amount of reactant in grams in a container at a temperature and amount produced in moles, calculate Kc: A quantity of 6.75 g of SO2Cl2 place in a 2.00 L flask. At 648 K, there is 0.0345 mol of SO2 present. Calculate Kc for the reaction. SO2Cl2(g) f/r SO2(g)+Cl(g)

Acid-base titration; density & specific heat of a solid

1.What data is collected in a titration? 2.How would I be able to find what the volume of 0.10M HCl should be needed to titrate .136 g Na2CO3 according to the reaction equation: Na2CO3(aqueous) +2HCl(aqueous)  2NaCl(aqueous) + H2O(liquid) + CO2(gas) 3.How would I determine the density of a solid using water di

Molarity and Solubility

1) If ZnCO3 (solid) is insoluble in water, but dissolves in excess 6.0 molar HCl (aqueous), how would pull out the proper equation that would support it? 2) How would you go about finding how many mL of 2.00 molar NaOH (Aqueous) solution are required to neutralize 1.858 g of KHC8H4O4 (it's formula weight being 204.22)? An

Reactions within equations and properties of acidity

A reaction occurs for each of the following below. How do you differentiate between the different driving forces? (a driving force can either be the transfer of electrons; the formation of a precipitate, etc.) 2Na(s) + 2H2O(l) --> 2NaOH(aq) + H2 KOH(aq) + HF(aq) --> KF(aq) + H2O(l) NaF(aq) + HCl(aq) --> NaCl(aq) + HF(

Thermodynamics Question

I solved part a of this problem easily. The rest of this problem has me stumped. I already have the solutions to these problems, but it's arriving at these solutions that has made me pull my hair out!


Calculate the heat of decomposition for this process at constant pressure and 25o: CaCO3(s) ---> CaO(s) + CO2(g)

Chemistry Based Calculations: Molar Solubility

Hi, I need some assistance with the following questions: 1. Calculate the molar solubility of AgCl in a 1.00L solution containing 10.0g of dissolved CaCl2. 2. Compare the molar solubility of Mg(OH)2 in water and in a solution buffered at a pH of 9.0.

Electrolyte Concentration and Polarization Potential

I am having some trouble with this question. Question: a) A copper refining cell is operating with an electrolyte which contains 0.05 m Sn2+. At what concentration of Cu2+ will the tin start to plate out in preference to the copper? The cell temperature is 40 degrees Celsius. b) A polarization potential arises from a con

Solubility Constant, Ksp of Reactant

The chemical reaction representing the soluability of AGBr is: AgBr (right and left arrow) Ag^+ +Br^- This can be written as: AgBr+ 1e^- (right arrow) Ag + Br^- Eo=.071 V Ag (right arrow) Ag^+ +1e^- Eo=-.800 Using this data, what is the solubility product constant, Ksp, of AgBr @ 25 Celsius?

Calculating cell potential...

Calculate the cell potential @ T=25 celsius assuming ideal solutions Fe | Fe^2+ (1.43 *10^-5) || Fe^2+ (5.00*10^-4M) | Fe The double line represents a salt bridge. I need detailed description of what they are talking about here - I haven't a clue!!

Rate Law for Proposed Mechanism

Consider the reaction 2NO(g) + O2 ---> 2NO2 (g). The following mechanism has been proposed to explain the experimental rate law: 1. 2NO --> and <-- N2O2 (fast) 2. O2 + N2O2 --> 2NO2 (slow) Give the rate law for the proposed mechanism. If necessary, use the pre-equilibrium assumption to determine an expression for the co

Rate Constant with Temperature Changes

Rearrangement of methyl isonitrile to acetonitrile has activation energy of 25.0 kJ/mol and a rate constant of 8.1*10^-4s-1 @ 80 Celsius. what is the value of the rate constant @ 255.0 celsius?

Half-life of first order process

A reactant undergoes a dissociation reaction A r arrow 2B which follows first order kinetics. The initial concentration of reactant A is .4000 M and after 75.00 hr the concentration of A decreases to 0.0816 M. Determine the half-life of the first order process. There must be a simple equation for this, but my textbook must a

Mathematics of pH Acidity

If 50.0 mL of a 0.1 solution of HOAc (Ka = 1.8 x 10^-5) has been titrated to the equivalence point with 0.1 M NaOH solution, what is the pH of the resulting solution? Please explain the math. Thanks.

Level of pH Acidity

Calculate the pH of a 1.0 M solution of NH4Cl with the following parameter given: Kb=1.8 x 10^-5 for NH3