Share
Explore BrainMass

General Chemistry

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?

Measuring Water Hardness

In an experiment for measuring water hardness in a water sample, using Atomic Absorption Spectrophotometry, I obtained a value of 173.74 ppm hardness for my water sample. Using EDTA determination, I obtained a value of 440 ppm hardness for my sample. In both these methods, I was measuring the hardness in relation specifically to

Hazardous Dyes

Question: Many dyes used in food products are classified a hazardous chemicals in their pure form. Why then can they be safely used in those food products?

General Chemistry

4.60 You have 505 ml of a 0.125M HCI solution , and you want to dilute it to exactly 0.100 M. How much water should you add?

8 precipitate of magnesium flouride

Will a precipitate of magnesium flouride form when 200.0 milliliter of 1.9x10^-3mol/Litre MgClsubnumber2 solution is added to 300.0 milliliter of 1.4x10^-2mol/Litre NaFsolution? (ksubletterssp(MgFsubnumber2)=6.9x10^-9) Briefly explain by showing your numerical calculations show work. thanks

Conversion factors

Convert the following to the required units: 550 uL (microliters) per hour to milliliters per day Please show steps

Barium hydroxide

Write a balanced chemical equation, for the reaction that occurs, when Solid barium hydroxide, dissolves in water. Thank you

Half life

1) Radioisotopes such as aluminum -26, which is believed to have been present in the solar system when earth was formed but can no longer be detected, are known as extinct radionuclides. The half-life for the decay of aluminum -26 is 7.20 x 10 ^5 years. How many years did it take for 99.99% of the aluminum -26 to decay? If

Electromagnetic Waves: Radio Message from Mars

At its closest approach, Mars is 56 million km from Earth. How long would it take to send a radio message from a space probe of Mars to earth when the planets are at this closest distance?

Molar solubility

Calculate molar solubility of CuI in 1.0 M NaI. Assume the highest complex formed is CuI2 - .

Precipitation

Solid Na2SO4 is added to a solution that contains 0.150 M Ba 2+ and 0.0800 M Ca2+. Which sulfate precipitates first, BaSO4 or CaSO4? What calculations would porve this? What should be the concentration of sulfate ion for the best separation?

Resonance Forms of BF3

The question goes like this. Boron often forms compounds that do not comply with the octet rule that are termed electron deficient. BF3, whose structure is shown below on the left, is an example of an electron deficient compound. Note that the central boron atom is only surrounded by 6 valence electrons. The resonance struct