Asolution is prepared by adding 50.00 g of lactose (milk sugar) to 110.0 g of water at 55 °c. the partial pressure of water above the solution is torr. the vapor pressure of pure water at 55 °c is 118.0 torr. the mw of lactose is 342.3 g/mol. a solution is prepared by adding 50.00 g of lactose (milk sugar) to 110.0 g of water at 55 °c. the partial pressure of water above the solution is torr. the vapor pressure of pure water at 55 °c is 118.0 torr. the mw of lactose is 342.3 g/mol. 156.8 2.757 115.2 282.3 81.1

Explanation:

Let’s call water Component 1 and lactose Component 2.

According to Raoult’s Law,  

where

p₁ and p₂ are the vapour pressures of the components above the solution

χ₁ and χ₂ are the mole fractions of the components

p₁° and p₂° are the vapour pressures of the pure components.

Data:

m₁ = 110.0 g;    p₁° = 118.0 torr

m₂ = 50.00 g; p₂° =    0    torr

1. Calculate the moles of each component

2. Calculate the mole fraction of each component

3. Calculate the vapour pressure of the mixture

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.