Answer:
The molar enthalpy of evaporation of water at 100.0°C is 40 kJ
Explanation:
Calculation of the moles of as:-
Mass = 0.702 g
Molar mass of = 18 g/mol
The formula for the calculation of moles is shown below:
Thus,
Given that:-
It means that when 0.039 moles of water undergoes evaporation, 1.56 kJ of energy is used
Also,
When 1 mole of water undergoes evaporation, of energy is used
<u>The molar enthalpy of evaporation of water at 100.0°C is 40 kJ</u>
Answer:
Molar mass of vitamin K = 450.56\frac{g}{mol}[/tex]
Explanation:
The freezing point of camphor = 178.4 ⁰C
the Kf of camphor = 37.7°C/m
where : m = molality
the relation between freezing point depression and molality is
Depression in freezing point = Kf X molality
Where
Kf = cryoscopic constant of camphor
molality = moles of solute dissolved per kg of solvent.
putting values
2.69°C = 37.7°C/m X molality
molality = 0.0714 mol /kg
moles of vitamin K = 0.0714X0.025 = 0.00178 mol
we know that moles are related to mass and molar mass of a substance as:
For vitamin K the mass is given = 0.802 grams
therefore molar mass =