On a cool, rainy day, the barometric pressure is 746 mmhg. calculate the barometric pressure in centimeters of water (cmh2o) (d of hg = 13.5 g/ml; d of h2o = 1.00 g/ml).

100.71 cm H2O

Explanation:

In a fluid column barometer, the height of the fluid column is proportional to the pressure. The pressure is by definition:

, where F is a force and A is the area.

In a column barometer the force is given by the weight of the fluid:

, and the mass may be expressed as , where is the density and V is the volume.

Replacing this in the pressure definition:

In a constant cross section area column, the volume may be calculated as:

where A is the area and h the height. Replacing this in the previous equation:

Different columns may be over the same pressure, so:

Dividing each part for gravity constant:

And isolating hw:

mm

It is equal to 1007,1 cm.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.