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General Chemistry

Pi and Sigma bonds

Why or why isn't it possible to have pi bonds between two atoms without there being a sigma bond?

Dalton's Law of Partial Pressure

A mixture of helium and neon gases is collected over water at 28.0 C and 745 mmHg. if the partial pressure of helium is 368 mmHg, what is the partial pressure of neon?

Finding the number of molecules of a virus

A certain strain of tobacco mosaic virus has Mm = 4 *10^7 kg/k mol. How many molecules of the virus are present in 1 cm^3 of a solution that contain0.1mg of virus per cm^3

Finding volume in a molarity problem

What volume, in milliliters, of a 2.00 M aqueous KOH solution would be needed to neutralize a) 110.0 mL of 0.0550 M aqueous H2SO4? b) 45.00 mL of 2.50 M aqueous HCl?

Calculating Relative Humidity

A closed vessel contains moist air at 20 degree celcius, the relative humidity being 30 %. What would be the relative humidity become if the vessel were cooled to 10 degree celcius ? SVP of watyer at 20 deg celcius = 17.5 mm SVP of water at 10 deg celcius = 9.2 mm

How much energy does a hydrogen atom give up?

A Hydrogen atom, treated as a point mass, is confined to an infinite one-dimensional square well of width 1.0nm. How much energy does it have to give up to fall from the level with 5 to the lowest energy level? The answer needs to be in Joules. This problem deals with quantum part of Physical chemistry.

Quantum numbers

Which element(s) has an outermost electron that could be described by the following quantum numbers: (3,1,-1,+1/2) ?

Reasons for iron discolouration

A shipment of iron-fortified powdered baby formula has been rejected by the buyers in China because the power is off-color. The color of the powder should be cream-colored, but this shipment is reddish-brown to gray. Investigation by the manufacturer shows that the manufacturing process is simply "bucket chemistry". This mean


Explain why each of the following integrals must be 0 when the functions are hydrogen-like wavefunctions: <2p1|Lz|3p-1> and <2p0|Lz|2p0> Show that taking the lithium spin orbitals in a Slater determinant as 1sa, 1sb, and 1s(c1a+c2b) where c1 and c2 are constants gives a wavefunction that equals zero. Tthe a and b are alp

Solve: Volume and Torr Pressure

If a gas occupies 625 mL at 0 Celsius and 760 torr pressure, what will its volume be at 373 degree C and 1520 torr pressure?

Significant Digits and Unit Conversion

1) How many significant figures are there in the answer to the following problem? (8.881*.02100) + .590? 2) A parsec is 206,265 times the distance from earth to the sun. If the distance is 8.000 million miles, express the distance of a parsec in miles in scientific notation.