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Physical Chemistry

Lewis Structures, Hybrid orbital

1. Draw the Lewis structure for OF2 (small 2 at bottom) What are its electron-pair and molecular geometries? decribe the bonding in the molecule in terms of hybrid orbitals. 2. Draw the Lewis structure for C1F 2 + (small s at bottom and small + at top) What are its electron-pair and molecular geometries? decribe the bonding i

Calorimetry involving heat of solution of NaOH(s)

A lab experiment dealing with the properties of a coffee cup calorimeter was completed. One of the procedures involved measuring the temperature of 50mL water placed in a calorimeter for 3 minutes, and then adding NaOH(s) pellets and measuring the temperature for 4 more minutes. I have several temperature measurements, but I am

Relationship between Refractive index and Mole Fraction

How can you use refractive indices to calculate weight % composition of a distillate and its residue? How can you convert the weight % composition to mole fractions? Could you please show me how they relate in mathematical form?

Rates and electrochemistry

1. Step 1: Cl2 ------ 2Cl (fast) Step 2: CHCl3 + Cl -------- CCl3 + HCl (slow) Step 3: CCl3 + Cl ------------CCl4 (fast) Identify the rate determining step, reaction intermediates and the experimental rate law (intermediates can not be in the rate law) 2. For the half-reaction XeF2(aq) +

Rates and electrochemistry

The numerical value of the rate constant for the gaseous reaction 2N2O5------- 4NO2+ O2 was found to be 5.8*10-4. The initial concetration of N205 was 1.00mol/L. Assuming all measurements are recorded in seconds, determine the tim required for the reation to be 60% complete if the reaction is second order

Thermodynamics Initial and Final Volumes

1. 5.30 moles of gas, initially at 25 degrees celcius and 5.00 atm pressure, was allowed to expand adiabatically( with no heat exchange between systen and surroundings) against a constant external pressure of 1.50 atm until the initial volume had trebled. The heat capacity of the gas was known to be 37.1 J/ degree celuius mol

Change of Internal Energy, Entropy, Volume with Temperature

The two figures show Cp VS T for various transitions. I need to know what the graph would look like for: 1. u (internal energy) vs T 2. S (Entropy) vs T 3. and V vs T for a first order (discontinuous) transition. Extra Info: FOr the equilibrium phase transitions at constant T and P (temperature and pressure) t

Electrode Chemistry

An ammonium ion selective electrode responds to both NH4+ and H+, but not to NH3. (pKa=9.244 for NH4+) A) What pH conditions must be imposed to ensure the electode properly represents toe activity of NH4+ B) Why is the ionic strength an important factor when using this or any ISE? How can you compensate for this effect?


How would you prepare a liter of "carbonate buffer" at a pH of 10.10? Ka = 4.2 times ten to the negative 7(carbonic acid) Ka = 4.8 times ten to the negative 11(bicarbonate ion) It says the key to solving the problem is picking the correct Ka value. How do I know which one to work with?

AP Chemistry Test Review: Gases

(See attached file for full problem description) --- 31. A sample of H2 gas occupies 615 mL at C and 575 mm Hg. When the gas is cooled, its volume is reduced to 455 mL and its pressure is reduced to 385 mm Hg. What is the new temperature of the gas? 54. Hydrogen can be made in the "water gas reaction." If you

Blending of Wines with Acid

I need some help with this question: Two wines are available for blending: One tank of 1000 L has a Titratable Acidity of 9.0 g/L and another tank containing 2000 L has a Titratable Acidity of 0.6 g/L. How much volume do you need to blend to make the 9.0 g/L Titatrable Acid wine equivalent to 7.2 g/L? What is the final volu

Ions being reduced or oxidized

*** Please see file for full description*** 1. Into each of three potatoes insert 1 copper and 1 zinc probe. The probes should be inserted to a medium depth inside the potatoes and should be spaced within about an inch of each other. The probes should NOT touch inside or outside of the potato. IMPORTANT: To illuminate an

Mass of Material

Calculate the mass of material required if 1000 calories of energy causes a change from -27ºF to 91ºC and the specific heat capacity is 0.25 joules/gram-degree C. The distance planet Inverse has a unique temperature scale. Their degree is not equivalent of our Celsius degree; they measure the freezing point of water as 100

Assorted AP Chemistry Questions

Consider the reaction. Mn3N2 (s) +H2O (l) → Mg(OH)2 (s) + NH3 (g) a) Balance the equation and name each compound. b) How many moles of Mg(OH)2 are produced from .319 mol of magnesium nitride? c) How many grams of water are necessary to produce 4.39 mol of ammonia? d) If 12.48g of magnesium hydroxide are

Titration Chemistry Problems

Consider two solutions. One solution is 0.1115 M Ca(OH)(2). The other is 0.1050 M HClO(4). a) Write a balanced equation for the reaction between the two solutions. b) How many mL of Ca(OH)(2) will be required to neutralize 25.00 mL of the HClO(4)? c) If a student starts to titrate 31.39 mL of the Ca(OH)(2) solut

AP Chemistry Problem

1: Consider mixing solutions of silver nitrate and calcium chloride. a. write a net ionic equation for the formation of the precipitate. b. If 200.0 mL of .300 M silver nitrate are mixed with 350.0 ml of .500 M calcium chloride, how many grams of precipitate are formed? How many moles of each ions are present after orecip

Dissolution of monoprotic acid

A 0.1mol/L aqueous solution of weak monoprotic acid (contains one ionizable hydrogen atom) has a hydrogen ion concentration of 0.001mol/L. The value of the ionization, Ka, for this acid is: a) 10^-5 (10 to the power of -5) b) 10^-2 (10 to the power of -2)

Helium balloon

If a helium balloon breaks loose it rises into the atmosphere and at some point bursts. Explain why?

Vacuum Question

Materials vacuum chamber and pumper large marshmallow balloon Procedure Wear safety goggles. 1. Place one large marshmallow in the vacuum chamber. 2. Cover the chamber with the dome and insert the pumper into the rubber septum. 3. Raise and lower the pumper slowly and observe what happens to the marshmallow. 4. The

physical chemistry

One problem that we will continue to face as the population of the earth steadily increases is fresh water. Even though there is an abundance of water on this planet, less than 5% of it can be used to sustain life. Therefore, new ways of purifying water are being developed. One of the best recent developments is using reverse

Standard Enthalpies of Reaction

50 g of C16H34 are burned with insufficient oxygen for complete combustion to CO2. C16H34(s) + 16.5 O2(g) -> 16 CO(g) + 17 H2O(l) and some of the reaction forms CO2 and H2O(l) in the reaction C16H34(s) + 24.5 O2(g) -> 19CO2(g) + 17H2O(l) (P=1 bar, T=298.15K, heat change = -1945.2 kJ) 1. Compute percent C16H34 that reacted

Various Basic Chemistry Problems - Mole, Mass and other Calculations

1) When a mole of C2H4 is combusted it reacts with 3 moles of O2 to produce CO2 and H2O. How many moles of CO2 and how many moles of H2O are produced? 2) What is the mass in grams of 4.25 moles of Mg (NO3)2? 3) The overall reaction producing iron from an ore in a blast furnace is: Fe2O3 + 3CO --> 2Fe + 3CO2 How many

Calculating molar concentrations of acetic acid

1) Calculate the hydrogen ion concentration and the pH of the solution formed when 0.020 gram-formula weight of nitric acid is added to one liter of aqueous 0.20 M ammonia solution. Assume no significant volume change upon addition of the acid. 2) Calculate the molar concentration of acetic acid at equilibrium in an acetic ac

Ferrous ion reaction

How do I calculate the moles of iron (ore sample) and how do I calculate the mass percent of iron in the ore from this problem; Ferrous ion reacts with permanganate ion Mno4 in acidic solution to produce the ferric ion Fe3. A 6.893 gram sample of ore was mechanically crushed and then treated with HCl which oxidized all the ir

Solve: Molarity and Molality

Question: Ethylene glycol, C2H6O2 (MW=62.1mol) has a density of 40.0 mass percentage and a solution of ethylene glycol in water is 1.0514 g/mL at 20 EC. Calculate the molality of the solution. Calculate the molarity of the solution.

Calculating vapor pressure using temperature

Hi, Please explain as ELEMENTARY as possible. Thank you (-: A liquid has a heat of vaporization of 35.5kJ/mol and a boiling point of 122 EC at 1 atm. What is its vapor pressure at 109EC?

Solve: Molarity

Please help with understanding the math for the following question: Question: A solution is prepared by dissolving 17.75 g of sulfuric acid (H2S04;MW = 98.0 g/mol) in 93.2 g of water. If the density of the solution is 1.1094 g/mL, what is the molarity of the sulfuric acid?

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).

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