Stoichiometry

Question 1

Ksp for [M+][X-] (MX -> M+ + X-)

Answer 1

Ksp= x^2

Question 2

Ksp for [M2+][X-]^2 (MX2 -> M 2+ + 2X-)

Answer 2

Ksp= 4x^3

Question 3

Ksp for [M3+][X-]^3 (M’X3 -> M’3+ + 3X-)

Answer 3

Ksp= 27x^4

Question 4

Solubility rule: Salts of +1 cation (non-transition) and -1 anion

Answer 4

Soluble in water at room temp. (silver halide insoluble, sodium salt soluble)

Question 5

Solubility rule: Nitrate (NO3-) salts

Answer 5

large anion that forms weak lattice interactions and strong H+ bonds with water, so most nitrate salts are water-soluble

Question 6

Solubility rule: Salts with 2- or 3- anions

Answer 6

Generally insoluble in water, excluding sulfate (SO4(2-))

Question 7

Solubility rule: Oxide (O2-) and hydroxide (OH-) salts

Answer 7

Only slightly water-soluble. (KOH and NaOH are exceptions, v soluble)

Question 8

Why is a small hole present in the cap of the flask in the Dumas experiment?

Answer 8

To allow the vapor pressure in the flask to equilibrate with the atmospheric pressure

Question 9

What is the purpose of the Dumas experiment

Answer 9

To determine the molec mass of an unknown liquid

Question 10

First salt to precipitate after an anion is added has:

Answer 10

lowest molar solubility of all salts in solution

Question 11

What happens to Ksp and solubility when acidity of saturated Mg(OH)2 is increased?

Answer 11

Additional MgOH2 will dissolve and Ksp will be unchanged

Question 12

Beer’s Law

Answer 12

States that absorbance depends on molar absorbitivity constant, concentration, and path-length

Question 13

EG: Adding 5 parts water to 0.6M solution gives you:

Answer 13

0.1M solution. Adding 5 parts water gives new volume 6x original. M1V1=M2V2.

Question 14

EG: What is the [Cl-] after mixing 50mL 0.1M KCl with 25mL of 0.2M MgCl2

Answer 14

Find the weighted average. So 2/3 KCL and 1/3 MgCl2
0.4(BOTH Cl)0.3333= 0.13333, 0.1.66666= 0.0666,
so roughly 0.2 M Cl-

Question 15

Mass percent

Answer 15

Mass atoms/ mass compound x100%

Question 16

When solving empirical formula assume

Answer 16

100 g sample

Question 17

Hydrocarbon must have an ____ # H+

Answer 17

Even

Question 18

Oxidize hydrocarbon gives

Answer 18

Co2 and h2o

Question 19

Molarity

Answer 19

Moles solute/ L

Question 20

Molality

Answer 20

Moles solute/ kg solvent

Question 21

Molality does not change with ____

Answer 21

Temperature

Question 22

Mass percent

Answer 22

=Mass atoms/ Mass compound X 100%