What mass (in g) of urea (co(nh2)2) in 100.0 g of water is needed to decrease the vapor pressure of water from 55.32 mmhg of pure water to 54.21 mmhg for the solution? the temperature is held constant at 40oc.

6.7 g

Explanation:

As the relative lowering of vapor pressure is directly proportional to the amount of dissolved solute.

The formula for relative lowering of vapor pressure will be,

where,

= vapor pressure of pure solvent  (water) = 55.32 mmHg

= vapor pressure of solution = 54.21 mmHg

= mass of solute  (urea) = ? g

= mass of solvent  (water) = 100 g

= molar mass of solvent (water) = 18 g/mole

= molar mass of solute (urea) = 60 g/mole

Now put all the given values in this formula ,we get the vapor pressure of the solution.

Therefore, 6.7 g of urea is needed in 100.0 g of water is needed to decrease the vapor pressure of water from 55.32 mmHg of pure water to 54.21 mmHg for the solution.

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.

increased stability in the completion of fluorine's outer shell.