Chemistry Third Quater Test - Answers

AP CHEMISTRY THIRD QUARTER TEST Class 2010 FORM A NAME: 1- UL MULTIPLE CHOICE: Place the letter of the best answer in the blank provided. B 1) The data in the table below were obtained for the reaction X + Y → 2 Experiment Initial X (molL) Initial Y Initial rate of formation of Z (mol/L) (mol/L min) 0.10 0.20 0.30 4.0 €-4 0.60 1.6 €-3 0.20 0.30 4.0 €-4 Which of the following is the rate law for the reaction? a) Rate= k (x/* b) Rate= k [y]* c) Rate= k (x) (y) d) Rate= k (X)' (y) e) Rate= k (x] y' A 2) Given: Acid HCHO: HC,H,02 HCIO HF Ka 1.8 €-4 1.8 e-5 3.0 €-8 6.8 e-4 Which one of the following is the strongest base? a) CIO d) CHO; b) C,1,0; e) F с) HO _3) What is the maximum solubility of magnesium hydroxide in a solution of pH 11? (Ksp = 1.8 e-11) a) 1.8 e-5 b) 3.4 €-5 с) 4.5 e-6 d) 7.1 e-7 e) 3.4 e-8 D _4) What is the Kp for the reaction: 2 A2 (g) + B (s) → 2 D2 (g) at 100 K if the Kc equals 6.0 e5? (R=0.08) a) 4.8 e5 b) 7.5 €4 c) 3.8 e7 d) 6.0 e5 e) 9.3 €4 What is the approximate pH of a buffer prepared by mixing 0.10 mol of HF and 0.10 mol of NaF in 1.0 Liter? Ka for HF = 6.8 €-4 a) 1| b) 3 c) 7 d) 11 e) can't tell 6) When the following reaction is at equilibrium, the reaction can be shifted to the products by PbS (s) + 3/2 02 (g) €→ PbO (s) + SO, (g) H = -414 kJ a) decreasing the pressure and keeping the temperature constant b)| c) heating the reaction and keeping the pressure constant c)| adding more PbS decreasing the volume and keeping the pressure constant AP CHEMISTRY THIRD QUARTER TEST e) adding a catalyst What is the approximate pH of a solution prepared by mixing 40.0 mL of 0.100 M NaOH with 40.0 mL of 0.300 M HCI? а) 1.0 b) 6.0 c) 7.0 d) 9.0 e) 12.0 Use the following data for questions 8 and 9. Hypothetical reaction A + 2B + C → Products: Exp A (М) 0.02 В (М) 0.02 0.02 0.01 0.04 0.01 0.04 0.01 C (M) 0.02 0.02 0.02 0.03 rate (M/sec) 1.6 €-3 8.0 €-4 1.6 e-3 1.6 €-3 8) What is the rate law? a) Rate= k [A] (B) ' (C] c) | Rate= k [AJ (B] b) Rate= k (A] (B)? d) Rate= k [A| [C] e) Rate= k [A] (B] [C] A 9) Which of the following is a possible rate determining step for the reaction? a) A + B → intermediate, d) 2B → intermediate b) B + C → intermediate e) A + B + C→ Products c) A + 28 → intermediate E 10) toes ate late changection is Rate = JAY' I the concentration of A is tripled, how does the rate change? a) decreases by a factor of 1/2 d) increases by a factor of 1/3 b) increases by a factory of three e) increases by a factor of nine c) increases by a factor of eight / 1) For a particular salt, the solution process is endothermic. As the temperature at which the salt is dissolved increases, which of the following will occur? a) Ksp will increase and the salt will become more soluble. b) Ksp will decrease and the salt will become more soluble. c) Ksp will increase and the salt will become less soluble. d) Ksp will decrease and the salt will become less soluble. e) Ksp will not change and the salt will become more soluble. A sealed isothermal container initially contained 2 moles of CO gas and 3 moles of 12) He gas. The following reversible reaction occurred: 10 + 212 CO (g) + 2H2 (g) +→ CH,OH (g) - 2 Al equilibrium there was 1 mole of CH,OH in the container. What Was the fotal number of moles of gas present in the container at equilibrium? + ( AP CHEMISTRY THIRD QUARTER TEST a) 1 b) 2 c) 3 d) 4 e) 5 13) The table shown below contains concentration and rate data for this reaction: A + 28 → C Determine the rate law for this reaction. Exp 1| 21 Initial A 0.17 0.17 0.51 Initial B 0.23 0.46 0.23 Initial rate M/s 0.33 2.64 0.33 a) Rate= k [A] (B]* b) Rate= k(B)* c) Rate= k [AJ" d) Rate= k [A) (B) e) Rate= k (B}' F 14) If the acid dissociation constant, Ka, for an acid HA is 8 c-4 at 25°C, what percent of the acid dissociated in a 0.50 molar solution of HA at 25°C? 4 y? a) 0.08% b) 0.2% c) 1% d) 2% e) 4% 8x103 4y:4 1 18) Assume that the reaction described here is second order for both A and B: 2A + 28 → C * I' What units should you use for the rate constant? a) M'' sec' b) sec*" c) M'sec" d) M's'* e) k has no units _ 16) Which one of the following 0.1 M solutions would have the highest pH a) KCN (Ka HCN = 4.0x10*"°) b) NH,NO' (Kb NH3= 1.8x10") d) KCH,O, (Ka HCH,O, = 3x10*") e) NaC,H,02 (Ka HC,H,02 = 1.8×10°) c) NaCIO (Ka HCIO = 3.2×10*) 17) What volume of 0, 150 molar HCl is required to neutralize 25 0 ml. of 0,150 molar a) 25.0 mL b) 30.0 mL c) 40.0 mL d) 50.0 mL e) 80.0 mL F_ 18) HSO: + HO €* H0* + SO.* In the equilibrium represented above, the species that act as bases include which of the following? I. SO: a) Il only D; ili only d) I and !II| €; 1l anc il AP CHEMISTRY THIRD QUARTER TEST III. So? c) I and I!| B. 19) A 1 molar solution of which of the following salts has the highest ph? a) NaNO, b) Na, CO, d) NaHSO, e) Na,SO, c) NH, CI 20) A solution of calcium hypochlorite, a common additive to swimming pool water, is a) basic because of the hydrolysis by OCI b) basic because Ca(OH) is a weak and insoluble base c) neutral if the concentration is kept below 0.1 Molar d) acidic because of the hydrolysis by the Ca' ions e) acidic because of the acid HOCI is formed B 21) All of the following reactions can be delined as Lewis acid-base reactions except. a) A(OH), + ОН → А(ОН); d) NH, + NH2 → 2 NH, b) Cl + HO → HOCI + H° + Cr e) H° + NH, → NH/' c) SniCi, + 2C* → Snch? Е 22) на > нс,м0, » нЕм > н,0 » мн, Five acids are listed above in the order of decreasing acid strength. Which of the following reaction must have an equilibrium constant with a value less than 1? a) HCI + CN' +→ HCN + Cr | d) H,O + NH; €→ NH, + OH' b) HCI + H,0 +→ H,0 + сг e) HCN + C,H,O; +→ HC,H,0, + CN с) НСН,0г + ОН (→ С,Н,О; + Н,О С 23) H.0,0 + 24,0 → 2 4,0 * + с,О." Oxalic acid H¿C,O, is diprotic acid with Ka1 = 5.4 e-2 and Ka2 = 5.3 e-5. For the reaction above, what is the equilibrium constant? а) 5.36 e-2 b) 5.3 €-5 c) 2.8 e-6 d) 1.9 e-10 e) 1.9 e-13 D 24) Write the expression relating schubity to Ksp for silver sulide (Ag'S). 24 X. a) VKsp/2 b) VKsp/4 c) v Ksp/4 d) 3V Ksp/4 e) *Ksp/2 B 25) Estimale the pH at the equivalence point of 34.5 mL of 0.120 M ammonia being titrated with 0.150 M HCI. 4 K