Gen chem 9

Question 1

define solutions
why are gases defined as mixtures

are all mixtures solns and vice versa?

solvent is the component of the solution that does what after mixing?

what are three ways that solute molecules interact with the solvent?

Answer 1

solutions are homegeneous(the same throughout) mixtures of two or more substances that combine to form a single phase, usually the liquid phase
-gases are defined as mixtures because gas molecules dnt interact that much chemically

all solutions are mixtures but not all mixtures are solutions
the solvent is the component of the solution that remains in the same phase after mixing

-they move freely in the solvent and interact with it by by way of ion-dipole, dipole-dipole, or hydrogen bonding

Question 2

define solvation what is it also called and what is it called if water is used?
why is the dissolution of gases into liquids exothermic?
when new intermolecular interactions are stronger than original ones, what kind of process is solvation and at what temps is it favored? vice versa as well and what temps is it favored?
which one do most dissolutions favor?
when would the overall enthalpy change for the dissolution be close to zero?
what is an ideal solution?

Answer 2

solvation is the electrostatic interaction btween solute and solvent molecules, this is called dissolution and when water is the solvent it can be called hydration
-the dissolution of gas into liquids such as CO2 into water is an exothermic process becuz the only significant interactions that must be broken are those btween water molecules–CO2 as a gas shows minimal intermolecular interaction.
-the process is exothermic and the process is favored at low temps
-the process is endothermic and the process is favored at high temps(most dissolutions are of this type)
the overall enthalpy change for the dissolution would be close to zero if the overall strength of new interactions is equal to the overall strength of the original interactions
- an ideal solution is when the enthalpy of dissolution is zero

Question 3

what two things does the spontaneity of dissolution depend on ?
at constant temp and pressure, what increases upon dissolution?
why can water interact with each of the component ions in a salt water mix thru what-what interactions?
note that both dilute and concentrated solutions are still considered unsaturated if the max what has not been reached?
when the change in gibbs free energy for the dissolution reaction is negative at a given temp, the process will be what is the solute is said to be what?
at what molar solubility are solutes considered soluble?
molar solubility for sparingly soluble salts?

Answer 3

entropy and enthalpy
entropy
its because water is polar that it can interact with each of the component ions thru ion-dipole interactions
if the equilibrium conc has not been reached

• when the change in gibbs free energy for the dissolution reaction is negative at a given temp, the process will be spontaneous is the solute is said to be soluble
• when the change in gibbs free energy for the dissolution reaction is positive at a given temp, the process will be nonspontaneous is the solute is said to be insoluble
• above 0.1 M in soln
• less than 0.1 M in soln

Question 4

why is H+ never found alone in a solution? what is it found bonded to?
what are the seven solubility rules for aq solns?
-all salts containing NH3 and alkali metal (Group 1) cations are water what
-all salts containing nO3 and acetate anions are water what
-halides(cl, br, i) excluding flourides are water what with the exception of those formed with Ca2+, Sr2+ Ba2+ and Pb2+
- all metal oxides are what , with the exception of those formed with the alkali metals, ammonium, and CaO, SrO, and BaO all of which hydrolyze to form solns of the corresponding metal hydroxides
-all hydroxides are what, with the exception of those formed with the alkali metals, ammonium, Ca2+ Sr2+ and Ba2+
what are the two absolute solubility rules?

Answer 4

because a free proton is difficult to isolate; it is found bonded to an electron pair donor(carrier) molecule such as a water molecule
-all salts containing NH3 and alkali metal (Group 1) cations are water soluble
-all salts containing nO3 and acetate anions are water soluble
-halides(cl, br, i) excluding flourides are water soluble with the exception of those formed with Ca2+, Sr2+ Ba2+ and Pb2+
- all metal oxides are insoluble , with the exception of those formed with the alkali metals, ammonium, and CaO, SrO, and BaO all of which hydrolyze to form solns of the corresponding metal hydroxides
-all hydroxides are insoluble, with the exception of those formed with the alkali metals, ammonium, Ca2+ Sr2+ and Ba2+
-all carbonates phosphates sulfides and sulfites are insoluble, with the exception of those formed with the alkali metals and ammonium
absolute #1: all salts of group 1 metals and all nitrate salts are soluble