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General Chemistry

Nuclear equations: Example problems

8. Show that for this nuclear equation, the sum of the subscripts on the left is equal to the sum of the subscripts on the right . Then show that the sum of the subscripts on the left is equal to the subscripts on the right 239 94PU + 4 2He---> {243 96 Cm} --->242 96 Cm + 1 On 9.When 4.oo g of hydrogen nuclei fuse to form he

Lewis Structure Hybridization

4. The molecule pictured below is AZT. It is a widely used drug for the treatment of AIDS. The Lewis structure below is complete except for electron lone pairs. For this structure: a. Draw in all missing electron lone pairs. b. Write in the shape of the molecule at the atoms indicated by arrows attached to boxes with "shap

Sigma (σ) and pi (π) bonds

1. How many sigma (σ) and pi (π) bonds are in each of the following molecules? Molecule Number of σ bonds Number of π bonds Molecule Number of σ bonds Number of π bonds CO2 XeF3+ N2 Cl2CO CO32- ion BrO3_ 2. An iron atom is located in a molecule called an "iron-porphyrin" (or "heme") which has an import

Oil Drop Experimental Units

Please show how to solve the following problem: Repeat Millikan's oil drop experiment using a unit of your own devising (B) rather than the unit of Coulombs. You measure the charges on 4 different drops labeled a, b,c, d. You determine that drop a has charge 13.52 B, drop b has charge 3.359 B, drop c has charge 10.21 B, and

Valance Bands & Energy to Produce and Electron Hole Pair

3. A material has an effectively full valence band and an empty conduction band. Explain why that if these two bands overlap the material behaves as a metal and if they are separated by a few electron volts in energy the material is an insulator. 4. Calculate the minimum energy a photon must have to produce an electron hole p

Clinical Uses of Radioactivity & Decay

How long would it take for a radioactive isotope with a half life of 2 weeks to lose at least 70% of its radioactivity? Describe two clinical uses of Radioactivity.

Pressure Using a Manometer

An open-end manometer containing mercury is connected to a container of gas. The mercury in the arm attached to the gas is 13.6cm higher than the one open to the atmosphere. The atmospheric pressure is 1.05atm I have to find the pressure of the enclosed gas in torr.

MO theory and dissociation energy

Use simple MO Theory (LCAO-MO) to explain why the dissociation energy of neutral N2 is greater than the N2+ ion, but that the dissociation energy of the O2+ ion is greater than the O2 neutral.

AP Chemistry: Test Review

(See attached file for full problem description) --- I need full explanation of each step. Please help. 1. The helium ion, He+, has energy levels similar to those of the hydrogen atom, since both species have only one electron. The energy levels of the He+ ion are given by the equation En = - 5248.16 kj/mole n =

Percentage yields

A chemist isolates 17.43 g of product from a reaction that has a calculated theoretical yield of 21.34 g. What is the percentage yield?

Wavelength and Frequency Example Problem

Question 1: M. tuberculosis, the organism that causes tuberculosis, can be completely destroyed by irradiation with UV light with a wavelength of 254 nm. What is the frequency? Question 2: Aradio station's signal broadcasts at a freq. 1240kHZ. What is the wavelength in meters?

Distinguish Ionic or Covalent Bonding

While you are working in the lab your instructor hands you a vial of red, crystalline material and asks you to tell if it has ionic or covalent bonding. Describe at least one experiment you would do to answer the instructor's question.

Volatility

Suppose you were given samples of two different liquids. Describe how you would determine which one is more voliatile.

Conversions

The volume of a certain bacterial cell is 1.60 µm3. (a) What is its volume in cubic millimeters (mm3)? (b) What is the volume of 105 cells in liters (L)? [show all the conversion factors that were used in calculating the answers]

Particle in a Box Proportionality

A particle is constrained to lie along a one-dimensional line segment between 0 and a. The probability of finding the particle along this line segment is seen in attached file. A. Find the proportionality constant, ie., normalize the function. B. Calculate the expectation values of X and X^2 for n=1 and n=2. C. Find t

Dilution Processes

I need help in solving this word problem: A corrupt barman attempts to prepare 100ml of some drink by mixing 30ml of ethanol with 70 ml of water. Does he succeed? If not, what volumes should have been mixed in order to arrive at a mixture of the same strength but of the required volume?

Precipitation calculations

Precipitation Calculations. Will a precipitate of calcium sulfate (Ksp = 2.4 x 10-5) form when 50.0 mL of 0.00150 M calcium chloride and 25.0 mL of 0.0100 M sodium sulfate are mixed? Why or why not?

General Chemistry - Orbitals and Configuration

Which one of the following configurations depicts an excited oxygen atom? a. 1s22s22p2 b. 1s22s22p23s2 c. 1s22s22p4 d. [He]2s22p4 e. 1s22s22p1 In a ground-state manganese atoms, the _____ subshell is partially filled. a. 4s b

Which pair consist of equalities?

Which pair consist of equalities? a. 3 x 10^-3 mL and 3 L b. 7 x 10^2 g/mL and 7 x 10^-9 kg/L c. 6 x 10^2 mm and 6 x 10^-5 m d. none of these pairs are equalities Explain how you derived at the answer.

Populated Rotational State as a Function of Temperature

Using the Boltzmann distribution given below, determine Jmax (quantum number of the most intensely populated rotational state) as a function of temperature. Then find Jmax for CN+ at 298 K and 1100 K. and CN+ bond length is 0.129 nm the Boltzman distribution: (Ni/N)= (exp(-ei/KT))/(sigma j exp(-Ej/KT)).

Atomic Mass & Isotopic Abundance

The element boron consists of two isotopes, 10(superscript), 5(subscript)B and 11(superscript), 5(subscript)B. Their masses, based on the carbon scale, are 10.01 and 11.01, respectively. The abundance of 10(superscript), 5(subscript)B is 20.0%. What is the abundance of 11(superscript), 5(subscript)B?

Empirical and molecular formulae of ethylene

1. Ethylene glycol is used as automobile antifreeze. 6.38g og this compound contains 2.47g of carbon and 0.620g of hydrogen. The rest is oxygen. The molar mass is 62.0g/mole. What are the empirical and molecular formulas of ethylene glycol? (observe significant digits)

Calculate minimum OH

The solubility product of Mg(OH)2 is 1.2E-11. What minimum OH- concentration must be attained (for example, by adding NaOH) to decrease the Mg2+ concentration in a solution of Mg(NO3)2 to less than 1.9E-10 M?

Calculating volume of water evaporated

A 230mL sample of a 0.276 M CaCl2 solution was left on a hot plate overnight; the following morning, the solution is 1.10 M. What volume of water evaporated from the 0.276 M CaCl2 solution?