The vapor pressure of ethanol is 54.68 mm Hg at 25°C. How many grams of estrogen (estradiol), C18H24O2, a nonvolatile, nonelectrolyte (MW = 272.4 g/mol), must be added to 228.0 grams of ethanol to reduce the vapor pressure to 53.46 mm Hg ? ethanol = CH3CH2OH = 46.07 g/mol.

30.5 g of estrogen

Explanation:

Lowering vapor pressure formula → P° - P' = P° . Xm

P° → Vapor pressure of pure solvent → 54.68 mmHg

P' → Vapor pressure of solution → 53.46 mmHg

54.68 mmHg - 53.46 mmHg = 54.68 mmHg . Xm

0.0223 = Xm → This is the mole fraction for solute

Moles of solute / Total moles

Total moles = Moles of solute + Moles of solvent

Let's determine the moles of solvent → 228 g / 46.07 g/mol = 4.95 moles

Let's determine the moles of solute

Moles of solute / Moles of solute + 4.95 = 0.0223

Moles of solute = 0.0223 . Moles of solute + 0.110

0.9777 moles of solute = 0.110

Moles of solute = 0.110 / 0.9777 → 0.112

Now we can convert the moles to mass to finish the excersise:

0.112 mol . 272.4 g/mol = 30.5 g

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.