Quant Final

Solid Al(NO3)3 is added to distilled water to produce a solution in which the concentration of nitrate, [NO3-], is 0.10 M. What is the concentration of aluminum ion, [Al3+], in this solution? (A) 0.010 M (B) 0.033 M (C) 0.066 M (D) 0.10 M (E) 0.30 M

(B) 0.033 M

What is the order of concentration of the ions and molecules in a methylamine solution? Methylamine, CH3NH2, is a weak base. (a) CH3NH2 > OH¯ = HCH3NH2+ > H3O+ (c) OH¯ > CH3NH2 > HCH3NH2+ > H3O+ (b) OH¯ = CH3NH2 > HCH3NH2+ > H3O+ (d) OH¯ = CH3NH2 = HCH3NH2+ > H3O+

(a) CH3NH2 > OH¯ = HCH3NH2+ > H3O+

The exothermic dissolution of Mg(OH)2 (s) (Ksp = 1.8 x 10-11) in water is represented by the equation above. Which of the following changes will increase the solubility of Mg(OH)2 in an aqueous solution? A) Adding H+ B) Increasing the temperature C) Adding Mg(NO3)2 to the solution D) Adding Mg(OH)2 solid to the solution E) Two of these will increase the solubility

A) Adding H+ would decrease amount of OH so rxn would have to shift right to make more OH so the Mg(OH)2 would be more soluble in order to do this

Four students attempt to generate the maximum amount of precipitate in a gravimetric analysis. The table below shows the various conditions used by each student: Student #1 Student #2 Student #3 Student #4 Solution temperature Hot Cold Hot Cold Rate of precipitant solution addition Slow Fast Fast Slow Volume of solution used Large Large Small Small Which student used the best set of conditions to maximize precipitation? A. Student 1 B. Student 2 C. Student 3 D. Student 4

A. Student 1

Adding 2.5 mol of NaI solid to 1 L of a solution saturated with PbI2 solid will have what effect on the solubility of the PbI2? Ignore ionic strength here. A. decreases the solubility B. no effect on the solubility C. increases the solubility D. none of these

A. decreases the solubility

Which answer correctly represents the final expression for the solution shown below? 2.58242 ± 0.0032 A. 2.582 ± 0.0032 B. 2.582 ± 0.003 C. 2.583 ± 0.003 D. 2.6 ± 0.0032

B. 2.582 ± 0.003

Heating a precipitate in its original solution to a temperature just below its boiling point for extended period of time in order to produce more pure crystals is called: A. Thermogravimetric analysis B. Digestion C. Nucleation D. Precipitation from homogeneous solution

B. Digestion

If BaSO4 has a Ksp = 1.0×10−10 and the Ksp of MgF2 is 1.0×10−10, which salt has higher solubility (in mol/L) in pure water? A. BaSO4 B. MgF2 C. They have the same molar solubility D. None of the above

B. MgF2 Ksp BaSO4 = x*x Ksp MgF2 = x*x^2

X (positive) Y (negative) 0.779 0.880 Based on the activity coefficients, which ion, if either, behaves more ideally than the other? A. X B. Y C. They exhibit the same ideal behavior

B. Y

X (positive) Y (negative) 0.779 0.880 If the magnitude of the charges of each ion are the same, which ion, if either, is larger than the other? A.X B.Y C.They are the same size

B. Y

When comparing two experimental means, you find that tcalculated > ttable. Which of the following is the correct interpretation of this result? A. You accept the null hypothesis B. You reject the null hypothesis C. You reject the alternate hypothesis D.Another test is required before accepting or rejecting either hypothesis

B. You reject the null hypothesis

A student mixes dilute AgNO3 (aq) with excess NaCl (aq) to form AgCl (s), as represented by the net ionic equation above. Which of the diagrams below best represents the ions that are present in significant concentrations in the solution (Ksp for AgCl is 1.8 x 10-10):

C. Na+, NO3, Cl-

Consider ionic strength here! AgCl will have the highest solubility in which solution? A. pure water B. a solution containing 1.0×10−4 M Cl− C. a solution containing 1.0×10−4 M Ag+ D. a high concentration of NaNO3 solution

D. a high concentration of NaNO3 solution Do not want a common ion or pure water (common ions makes solution less soluble)

A technician determines the concentration of lead in water using two different instruments. If Fcalculated < Ftable for the two sets of data: I. The difference in standard deviations for the two instruments is significant. II. The difference in standard deviations for the two instruments is not significant. III. The data sets have the same means. IV. The data sets do not have the same means. A. I only B. I and IV C. II and III D. II and IV E. II only

E. II only

Name two desired properties of the product(s) of a gravimetric analysis:

Purity and Insoluble

Two students are being introduced to volumetric pipettes. They need to measure out 10.00 mL of a solution and transfer it to a beaker. The two students perform four trials, and their results are shown here: Trial Student A Student B 1 10.01 mL 9.99 mL 2 10.03 mL 10.02 mL 3 10.04 mL 10.01 mL 4 10.03 mL 9.98 mL Which, if either, student's results demonstrate systematic error

Student A

Consider the chemical system CO + Cl2 COCl2; K = 2.3 x 105 How do the equilibrium concentrations of the reactants compare to the equilibrium concentration of the product? a) They are much smaller. b) They are about the same. c) You can't tell from the information given. d) They are much bigger. e) They have to be exactly equal.

a) They are much smaller.

Beaker A: 0.10M in 50mL Beaker B: 0.10M in 125mL Beaker C: 1M in 50mL The Kb of beaker C is ______ the Kb of beaker A. a) Greater than b) Equal to c) Less than

b) Equal to

Beaker A: 0.10M in 50mL Beaker B: 0.10M in 125mL Beaker C: 1M in 50mL The pH of beaker A is ______ the pH of beaker B. a) Greater than b) Equal to c) Less than

b) Equal to

Which one of the following is the strongest acid? a) Acetic Acid, Ka = 1.8 x 10-5 b) HF, Ka = 6.8 x 10-4 c) HClO, Ka = 3.0 x 10-8

b) HF, Ka = 6.8 x 10-4

Beaker A: 0.10M in 50mL Beaker B: 0.10M in 125mL Beaker C: 1M in 50mL The pH of beaker B is ______ the pH of beaker C. a) Greater than b) Equal to c) Less than

c) Less than

Consider the reaction: 2SO2(g) + O2(g) 2SO3(g) For the system at chemical equilibrium, which of the following explains what happens after the removal of oxygen gas (assume constant temperature)? a) The amount of SO3(g) increases and the value for K increases. b) The amount of SO3(g) decreases and the value for K increases. c) The amount of SO3(g) stays the same and the value for K decreases. d) The amount of SO3(g) decreases and the value for K stays the same. e) The amount of SO3(g) increases and the value for K stays the same.

d) The amount of SO3(g) decreases and the value for K stays the same.

For the stepwise dissociation of aqueous H3PO4, which of the following is not a conjugate acid-base pair? a) HPO42- and PO43- d) H3PO4 and H2PO4- b) H2PO4- and HPO42- e) H2PO4- and PO43- c) H3O+ and H2O

e) H2PO4- and PO43-