Chemistry Chapter 9

Question 1

When new interactions are stronger than original ones

Is solution exothermic or endothermic

Is it favoured at high or low temperatures

Answer 1

Exothermic
Favoured at low temperatures

Question 2

When new interactions are weaker than original ones

Is solution exothermic or endothermic

Is it favoured at high or low temperatures

Answer 2

Endothermic
High

Question 3

Whether or not the dissolution will spontaneously occur depends on 2 thigns

Answer 3

Enthalpy change
Entropy change

Question 4

If Gibbs free energy change is negative will the reaction be sponataneous

Answer 4

Yes

Question 5

If Gibbs free energy change is positive will the reaction be sponataneous

Answer 5

No

Question 6

Which 2 types of salts are always water soluble

Answer 6

Group 1 metals and nitrate salts

Question 7

Are nitrate, acetate anions water soluble

Answer 7

Yes

Question 8

Most common insoluble products are

Answer 8

Pb2+ and Ag+

Question 9

Process of solvation

Answer 9

Breaking of intermolecular forces between solid particles, and between solvent particles to form intermolecular forces between the solute and solvent particles

Question 10

Describe the differences between solubility and saturation

Answer 10

Solubility is the amount of solute that’s contained in a solvent. Saturation is the maximum solubility of a compound at a given temperature, one cannot dissolve any more, so just by adding more at this temperature when it’s fully saturated.

Question 11

What is one way in which solubility of a compound can be increased

Solids and gases

Answer 11

Increasing temperature can help with solubility of solids

Decreasing temperature or increasing partial pressure of a gas can also increase the solubility of gases

Question 12

What is the formula for percent composition by mass?

What is the percent composition by mass of a saltwater solution at 100 g of the solution contains 20 g of NaCl

Answer 12

Solute mass/ solution mass times 100%

20%

Question 13

If 184 g of glycerol is mixed with 180 g of water, what will be the mole fractions of the two components?

Answer 13

Find the moles of each

Moles divided by total moles to get percentage

Water mole fraction is 0.83
Glycerol mole fraction is 0.17

Question 14

Molarity of solution equation

If enough water is added to 11 g of CACL2 to make 100 mL of solution what is the molarity of the solution?

Answer 14

you find moles of CACL2 first which is 0.1 mols

Then you use moles/ volume of solute in litres

Answer is 1M

Question 15

Molality of a solution formula

If 10 g of NHOH is dissolved in 500 g of water. What is the molality of the solution?

Answer 15

Find moles of NaOH first

Then you get 0.25 moles.

0.25/ kilograms of solvent = 0.5 m

Question 16

What is normality of solution

49g of H2SO4 in 0.5L of solution

Answer 16

Find moles of h2so4 whcih is 0.5

There is 2 protons donatable so 0.5*2 =1

Then we do equivalent/volume in litres

So 1/0.5=2N

Question 17

What is the dilution equation

A chemist wishes to prepare 300 mL of a 1.1 moles NAOH solution from a 5.5 moles NAOH stock solution . What value of stock solution should be diluted with pure water to obtain the desired solution.

Answer 17

MV=MV
Initial and final

Answer is 60mL

Question 18

What is ion product formula

Answer 18

IP =[A]^m [B]^n

Question 19

If IP< K sp then it is saturated or unsaturated

Willl solute continue to dissolve

Answer 19

Unsaturated
Yes it will

Question 20

If IP> K sp then it is saturated or unsaturated

Willl solute continue to dissolve

Answer 20

SuperSaturated
Precipitation will occur

Question 21

If IP= K sp then it is saturated or unsaturated

Willl solute continue to dissolve

Answer 21

At equilibrium
Saturated

Question 22

The molar solubility of FE(OH)3 in an aqueous solution was determined to be 4x10^-10 mol/L. What is the value for the Kip at teh same temperature and pressure for Fe(OH)3

Answer 22

7.5 x 10^-37

Question 23

What does Big Ksp mean

What does small Ksp mean

Answer 23

Big means dissolves a lot, small means dissolves almost none

Question 24

What does big Kf or small Kf mean

Answer 24

Big Kf means the complex forms very easily

Small Kf means complex forms weakly

Question 25

If you have a tiny Ksp. But huge Kf, what that mean

Answer 25

It means the reactant does not dissolve on its own, but the product mixed with the second reactant dissolves very quickly

Question 26

Calculate Ksp of Ni(OH)2 in water, given that its molar olubility is 5.2 * 10^-6M

Answer 26

Write equation first Then multiple by 2 to find molar solubility for OH Then fit it back into the ^2 of equation to find Ksp 5.62* 10^-16

Question 27

If Ksp of Ba(OH)2 is 5 x 10^-3. Calculate the ion product of the following solutions based on concentration of ba2+. Let’s say teh moles for it rn is 0.5M, how do you find the ion product of the other

Answer 27

Always barium x 2 = then 1 Then always plug into equation (0.5)(1)^2

Question 28

When solute is added to a solvent, does the Vapor pressure of solvent increase or decrease

Answer 28

Decreases

Question 29

If a solutions Vapor pressure is decreased. What happens to its boiling point

Answer 29

Increased

Question 30

What is the change in Vapor pressure when 180 grams of glycceraldehyde are added to 0.18L of water at 100 degrees

Answer 30

Find moles fo glyceraldehyge which is 2 mols Find moles of water which is 10 mol Total moles is 12 mol Mole fraction of glyceradhyde 2/12 =0.167 Mole fraction water is 10/12=0.833 Raoults law - mole fraction of water x pressure = 0.833*1=0.833 Change in Vapor pressure is 1-0.833=0.167 ( why we minus by 1 ? Because original water was just 1atm)

Question 31

400g of AlCL3 is dissolved in 1.5L of water at rom temperature, Kb is 0.512 . How much does the boiling point increase after adding the aluminum chloride

Answer 31

4K Van’t hoff factor is for 4 because 1 al and 3 cl Find moles of alcl3, which is 3 moles Find molality which is 3/1.5L=2 M Then plus into equation (I)(Kb)(m)= T 4 x 0.512 x2 =4.096K

Question 32

What is the equation for the boiling point or freezing point change

Answer 32

(I) x (molality) x (Kf or Kb)

Question 33

Waht is colliagtive property Give some examples

Answer 33

Are properties that depend on the amoutn fo solute present and not the identity of the solutes present. Boiling point elevation Freezing point depression Vapor pressure