TG4_Solutions

Indicate the INCORRECT statement regarding the vapour pressure (P⁰_vap) of a pure liquid

• P⁰_vap increases exponentially with the Temperature (T)

• It is mainly due to the broad distribution of the kinetic energy of the molecules of the liquid

• If Temperature increases, the fraction of molecules in gas phase decreases

• It is related with the intermolecular forces ocurring between liquid molecules

Choose the correct statement about the normal boiling point of a pure liquid

• It is constant with atmospheric pressure

• It depends on the amount of liquid (in moles)

• It decreases as the external pressure increases

• It increases with an increase in external pressur

Choose the correct statement regarding the Critical Temperature (T_c)

• Above the T_c a substance can not become liquid

• At T_c coexist three phases in equilibrium

• It is the minimum temperature at which a solid sublimes

• At T_c coexist the liquid and solid phases in equilibrium

Calculate the volume of 36% HCl by mass (density = 1.18 g/mL) required to prepare 1L of 2M aqueous solution (HCl = 36.45 g/mol)

• 172 mL HCl

• 202 mL HCl

• 61.78 mL HCl

• 72.9 mL HCl

Chosse the correct statement regarding the factors affecting the solubility of chemical substances

• Large molecules dissolve better than small ones in a given solvent

• For gases, solubility decreases with the Temperature

• The solubility of liquids is greatly influenced by external Pressure

• NaCl is expected to be insoluble in H₂O

Which would be the partial pressure of a solution with a concentration of 100 mL of N₂(g) per liter of solution? (Data: K_N2 = 1.051 · 10^-3 M/atm)

• 4.24 atm

• 6.8 atm

• 258 atm

• 150 atm

Calculate the vapor pressure of water at 20 ºC in a solution prepared by dissolving 10 g of sucrose (342.3 g/mol) in 100 g of water (18.02 g/mol). Data: Pº(H₂O, 20 ºC) = 17.54 Torr

• 17.45 Torr

• 254 Torr

• 127 Torr

• 15.98 Torr

When 1.921 g of nicotine is dissolved in 48.92 g of H₂O, the freezing point of the resulting solution decreses to -0.45 ºC. Calculate the molar mass of the nicotine. Data: K_f = 1.86 ºC mol/Kg

• 162 g/mol

• 258 g/mol

• 56 g/mol

• 589 g/mol

When phenol and water are mixed, it is expected that

• total insolubility is observed

• total solubility is observed

• partial solubilility is observed

• total miscibility is observed

For a mixture of Toluene and benzene, it is expected

• an ideal solution

• non ideal solution

• inmiscibility