SCH4U Kahoot Review Unit 4

OCV Chemistry, Grade 12 University Preparation (SCH4U) Ottawa-Carleton Virtual Secondary School 2020-2021 Mr. Daniel Cho-En Lee ( daniel.cho-en.lee@ocdsb.ca ) SCH4U Kahoot Review 4.1 1. We observe 2H 2 O 2 → 2H 2 O and O 2 , but not the reverse. This is because… ❏ O 2 and H 2 O are too rare ❏ ΔH of the reverse reaction is too negative ❏ The temperature is too high ❏ The E act of the reverse reaction is too great 2. The system reaches equilibrium. Which reactions are still happening? ❏ None ❏ Both forward and reverse ❏ Only the forward ❏ Only the reverse 3. Which must be true at equilibrium? ❏ [reactant] = [product] ❏ [reactant] = 0 ❏ k forward = k reverse ❏ forward reaction rate = reverse reaction rate 4. A ⇌ B, K eq = 1. In the beginning [B] = 2, [A] = 1. So... ❏ [B] will increase ❏ [A] will increase ❏ [A] and [B] will remain unchanged 5. A + B ⇌ 2C. K eq = 1. So at equilibrium... ❏ [A] = [B] = [C] ❏ 2[C] = [A] + [B] ❏ [C] 2 = [A][B] ❏ (2[C]) 2 = [A][B] 6. Which of the following affects K eq ? ❏ catalyst ❏ activation energy ❏ temperature ❏ initial concentration 1

OCV Chemistry, Grade 12 University Preparation (SCH4U) Ottawa-Carleton Virtual Secondary School 2020-2021 Mr. Daniel Cho-En Lee ( daniel.cho-en.lee@ocdsb.ca ) 7. In the reaction 2A ⇌ B, the forward reaction rate = 0.1[A] 2 , the reverse reaction rate = 0.2[B] 1 . K eq = ? ❏ 2 ❏ 1 ❏ 0.5 ❏ 0.2 8. A ⇌ 2B. What is K eq in terms of [A] and [B] at equilibrium? ❏ [B] / [A] ❏ 2 [B] / [A] ❏ [B] x [B] / [A] ❏ 2[B] x 2[B] / [A] 9. In the reaction 2A ⇌ B, at EQ, [A] = 0.33M = [B]. What is K eq ? ❏ 3 ❏ 1 ❏ 0 ❏ 0.33 10. N 2 O 4 ⇌ 2 NO 2 , K eq = 2. In the beginning there was no NO 2 , and [N 2 O 4 ] = 1 mol/L. What is [N 2 O 4 ] at equilibrium? ❏ 2 mol/L ❏ 1.5 mol/L ❏ 1 mol/L ❏ 0.5 mol/L SCH4U Kahoot Review 4.2 1. At 100ºC and 1 atm, which processes about water are in equilibrium? ❏ melting and boiling ❏ sublimating and depositing ❏ condensing and boiling ❏ there is no equilibrium 2. A sugar cube dissolved in water quickly. Which processes with the sugar are in EQ? ❏ dissolving and crystallizing ❏ sublimating and depositing 2

OCV Chemistry, Grade 12 University Preparation (SCH4U) Ottawa-Carleton Virtual Secondary School 2020-2021 Mr. Daniel Cho-En Lee ( daniel.cho-en.lee@ocdsb.ca ) ❏ reduces by 0.67x 9. A ⇌ B. Keq = 1. Initially [A] = 1M, [B] = 0M. If "x" M of B formed at equilibrium... ❏ (1 + x) / (1 - x) = 1 ❏ x / (1 - x) = 1 ❏ (1 + x) / x = 1 ❏ x / 1 = 1 10. A ⇌ 2B. Keq = 2. Initially [A] = [B] = 1M. If "x" M of A is consumed to reach EQ… ❏ (1 + x) / (1 - x) = 1 ❏ (1 + 2x) 2 / (1 - x) = 2 ❏ (1 + 2x) / (1 - 2x) = 2 ❏ (1 + x) / (1 - 2x) 2 = 2 SCH4U Kahoot Review 4.3 1. In NaCl (s) ⇌ Na + (aq) + Cl - (aq) , which chemical interactions about NaCl are breaking and forming? ❏ covalent bonds ❏ hydrogen bonds ❏ H + and OH - of water molecules ❏ ionic bonds and ion-dipoles 2. NaCl (s) ⇌ Na + (aq) + Cl - (aq) , What is the K eq expression? ❏ [Na + ][Cl - ] ❏ [Na + ][Cl - ] / [NaCl (s) ] ❏ [H 2 O (l) ] ❏ 1 3. How is the K sp of CaCl 2(s) expressed? ❏ [Ca 2+ ] [Cl - ] ❏ [Ca 2+ ] 2[Cl - ] ❏ [Ca 2+ ] [Cl - ] 2 ❏ [Ca 2+ ] ( 2[Cl - ] ) 2 4. Suppose K sp of CaCO 3 = 10 -8 . In the seawater right above the CaCO 3 seafloor… ❏ [Ca 2+ ][CO 3 2- ] >> 10 -8 ❏ [Ca 2+ ][CO 3 2- ] = 10 -8 4

OCV Chemistry, Grade 12 University Preparation (SCH4U) Ottawa-Carleton Virtual Secondary School 2020-2021 Mr. Daniel Cho-En Lee ( daniel.cho-en.lee@ocdsb.ca ) ❏ [Ca 2+ ][CO 3 2- ] << 10 -8 ❏ [Ca 2+ ] = [CO 3 2- ]= 10 -4 5. 10 mol NaCl is added to 1L of pure water to reach saturation. At EQ, [Na + ] = 5M. What is [Cl - ]? ❏ 10M ❏ 5M ❏ 2M ❏ 1M 6. NaCl is added to pure water to reach saturation. What is its K sp expressed by the [Na + ] at EQ? ❏ K sp = 1 ❏ K sp = [Na + ] ❏ K sp = [Na + ] [Na + ] ❏ K sp = 2 [Na+] 7. Suppose the K sp of NaCl is 36. In a saturated NaCl solution (nothing else), [Na + ] =... ❏ 36M ❏ 58.5M ❏ 6M ❏ 1M 8. CaCl 2 is added to pure water to reach saturation. What is K sp expressed by the [Ca 2+ ] at EQ? ❏ [Ca 2+ ] (2 [Ca 2+ ]) 2 ❏ [Ca 2+ ] (2 [Ca 2+ ]) ❏ [Ca 2+ ] [Ca 2+ ] 2 ❏ [Ca 2+ ] [Ca 2+ ] / [Ca 2+ ] 9. Ca(OH) 2 (K sp = 4 x 10 -6 ) is added to pure water to reach saturation. What is [Ca 2+ ] at EQ? ❏ 4 x 10 -6 M ❏ 2 x 10 -3 M ❏ 1 M ❏ 10 -2 M 10. Ca(OH) 2 (K sp = 4 x 10 -6 ) is added to a 1M Ca(NO 3 ) 2 solution to reach saturation. What is [Ca 2+ ] at EQ? ❏ 4 x 10 -6 M ❏ 2 x 10 -3 M ❏ 1 M 5

OCV Chemistry, Grade 12 University Preparation (SCH4U) Ottawa-Carleton Virtual Secondary School 2020-2021 Mr. Daniel Cho-En Lee ( daniel.cho-en.lee@ocdsb.ca ) ❏ heat is absorbed through the forward reaction 7. CaC 2 O 4(s) ⇌ Ca 2+ (aq) + C 2 O 4 2- (aq) . How to prevent kidney stones? ❏ eat more tofu, which contains Ca 2+ ❏ eat more spinach, which contains C 2 O 4 2- ❏ drink "soft" water ❏ drink "hard" water 8. Which slows down both forward and reverse reactions? ❏ increase temperature ❏ reduce pressure (gas system) ❏ reduce activation energy ❏ increase concentration 9. NaCl ⇌ Na + + Cl - , ΔH = +4 kJ/mol. What will happen if we heat up a saturated solution of NaCl (no undissolved salt)? ❏ the solution becomes unsaturated ❏ NaCl crystalizes ❏ no effect 10. In an 1M solution of glucose, the count of water molecules vs. glucose molecules is roughly… ❏ 100:1 ❏ 50:1 ❏ 18:1 ❏ 1:1 SCH4U Kahoot Review (sections 4.5a) 1. An acid... ❏ accepts H 3 O + ❏ accepts H 2 O ❏ donates H 2 O ❏ donates H + 2. HA (aq) + H 2 O (l) ⇌ H 3 O + (aq) + A - (aq) Literature K a = 0.01. Therefore... ❏ [H 3 O + ][A - ] / [HA][H 2 O (l) ] = 0.01 ❏ [HA][H 2 O (l) ] - [H 3 O + ][A - ] = 0.01 7

OCV Chemistry, Grade 12 University Preparation (SCH4U) Ottawa-Carleton Virtual Secondary School 2020-2021 Mr. Daniel Cho-En Lee ( daniel.cho-en.lee@ocdsb.ca ) ❏ [H 3 O + ][A - ] / [HA] = 0.01 ❏ [HA] - [H 3 O + ][A - ] = 0.01 3. The larger the K a of an acid "HA", the _____ of A - it produces in water. ❏ more ❏ less ❏ same 4. Which of the following is the weakest acid? (HF, HCl, HBr, HI) ❏ HF ❏ HCl ❏ HBr ❏ HI 5. Which acid has a larger K a ? (CH 3 COOH vs. HCl) ❏ CH 3 COOH ❏ HCl ❏ Same K a 6. Which of the following has a lower pH value? (1.0M HCl vs. 0.1M HCl) ❏ 1.0 M HCl ❏ 0.1 M HCl ❏ The pH values are equal 7. Which of the following has a lower pH value? (2.0M CH 3 COOH vs. 2.0M HCl) ❏ 2.0 M CH 3 COOH ❏ 2.0 M HCl ❏ The pH values are equal 8. What is the pH of a 0.01 M HNO 3 solution? ❏ 0.01 ❏ -2 ❏ 2 ❏ 100 9. What is the pH value of a 1M HCl solution? ❏ -1 ❏ 0 ❏ 1 8

OCV Chemistry, Grade 12 University Preparation (SCH4U) Ottawa-Carleton Virtual Secondary School 2020-2021 Mr. Daniel Cho-En Lee ( daniel.cho-en.lee@ocdsb.ca ) ❏ Equally likely 7. A protonated amine with K a = 1 x 10 -10 is more likely (R-NH 3 + vs. R-NH 2 ) in the blood (pH = 7.45) ❏ R-NH 3 + ❏ R-NH 2 ❏ Equally likely 8. After CO 2 reacts with water in the blood, which form is the most common? (H 2 CO 3 , HCO 3 - , or CO 3 2- ) ❏ H 2 CO 3 ❏ HCO 3 - ❏ CO 3 2- 9. Which will reduce as seawater acidifies? ([H 3 O + ], [H 2 CO 3 ], or [CO 3 2- ]) ❏ [HH 3 O + ] ❏ [H 2 CO 3 ] ❏ [CO 3 2- ] ❏ all of the above 10. Which will increase as seawater acidifies? (pH, [CO 3 2- ], [Ca 2+ ], CaCO3 (s) ) ❏ pH ❏ [CO 3 2- ] ❏ [Ca 2+ ] ❏ CaCO 3(s) SCH4U Kahoot Review (sections 4.6) 1. Which is NOT a base? (KOH, Ca(OH) 2 , H 2 CO 3 , NH 3 ) ❏ KOH ❏ Ca(OH) 2 ❏ H 2 CO 3 ❏ NH 3 2. Which base has the larger K b ? (NH 3 vs. NaOH) ❏ NH 3 ❏ NaOH 10

OCV Chemistry, Grade 12 University Preparation (SCH4U) Ottawa-Carleton Virtual Secondary School 2020-2021 Mr. Daniel Cho-En Lee ( daniel.cho-en.lee@ocdsb.ca ) ❏ equally large 3. Which of the following bases should have a low K sp in water? ❏ LiOH ❏ NaOH ❏ Ca(OH) 2 ❏ NH 3 4. What is the pOH of a 1M NaOH solution? ❏ 14 ❏ 13 ❏ 0 ❏ 1 5. What is pH + pOH at 25ºC? ❏ 0 ❏ 10 0 ❏ 10 -7 ❏ 14 6. What is the pH of a 1M NaOH solution? ❏ 14 ❏ 13 ❏ 0 ❏ 1 7. Which solution has a higher pH, 2M KOH or 2M NH 3 ? ❏ 2M KOH ❏ 2M NH 3 ❏ equally high 8. 2 H 2 O (l) ⇌ H 3 O + (aq) + OH - (aq) What is the K eq of this reaction at 25ºC? ❏ 7 ❏ 10 -7 ❏ 14 ❏ 10 -14 11

OCV Chemistry, Grade 12 University Preparation (SCH4U) Ottawa-Carleton Virtual Secondary School 2020-2021 Mr. Daniel Cho-En Lee ( daniel.cho-en.lee@ocdsb.ca ) 4. HA + H 2 O ⇌ H 3 O + + A - . At 25ºC, if the K a of HA is = 10 -5 , then the K b of A - = ... ❏ 10 -5 ❏ 10 -9 ❏ 10 -14 ❏ 10 -19 5. B + H 2 O ⇌ OH - + HB + . At 25ºC, if the K b of B is = 10 -7 , then K a of HB + = ... ❏ 0 ❏ 1 ❏ 10 -14 ❏ 10 -7 6. Acid #1’s pK a = 3. Acid #2’s pK a = 6. Which acid is stronger? ❏ #1 ❏ #2 ❏ equally strong 7. Acid #1’s pK a = 3. Acid #2’s pK a =6. Which acid's conjugate base is a stronger base? ❏ #1 ❏ #2 ❏ equally strong 8. pK a of HCO 3 - + pK b of HCO 3 - must be 14 at 25ºC, True or false? ❏ True ❏ False 9. pK a of H 2 CO 3 = 6.4, what is certain about the pK a of HCO 3 - ? ❏ < pK a of H 2 SO 4 ❏ = 7.6 ❏ > 6.4 ❏ = pK b of HCO 3 - 10. What is "14" at 25ºC? ❏ pK a of H 2 CO 3 + pK b of CO 3 2- ❏ pK a of H 3 O + + pK b of OH - 13

OCV Chemistry, Grade 12 University Preparation (SCH4U) Ottawa-Carleton Virtual Secondary School 2020-2021 Mr. Daniel Cho-En Lee ( daniel.cho-en.lee@ocdsb.ca ) ❏ pK a of H 2 PO 4 - + pK b of PO 4 3- ❏ pK a of HSO 4 - + pKb of SO 4 2- SCH4U Kahoot Review (sections 4.8) 1. How many moles of HCl is required to neutralize 100mL of 0.10M NaOH? ❏ 100 moles ❏ 10 moles ❏ 0.1 moles ❏ 0.01 moles 2. At the equivalence point (HCl + NaOH), what is the pH of the solution at 25ºC? ❏ > 7 ❏ < 7 ❏ = 7 3. How many moles of NaOH can completely neutralize 1L of 2M H 2 SO 4 ? ❏ 4 moles ❏ 2 moles ❏ 1 moles ❏ cannot neutralize 4. How many moles of NaOH is required to neutralize (reach equivalence point) 10mL of 1M CH 3 COOH? ❏ > 0.01 mole ❏ < 0.01 mole ❏ = 0.01 mole 5. At the equivalence point (NaOH + CH 3 COOH), what is the pH? (25ºC) ❏ > 7 ❏ < 7 ❏ = 7 6. At the equivalence point (HCl + NH 3 ), what should be the pH? (25ºC) ❏ > 7 ❏ < 7 ❏ = 7 14

OCV Chemistry, Grade 12 University Preparation (SCH4U) Ottawa-Carleton Virtual Secondary School 2020-2021 Mr. Daniel Cho-En Lee ( daniel.cho-en.lee@ocdsb.ca ) ❏ K b of conjugate base ❏ K w (water dissociation) ❏ K sp of C 3 (PO 4 ) 2 Hint: The pK a of the weak acid can be quickly estimated from point #2. Then, pK b of the conjugate base = 14-pK a SCH4U Kahoot Review (sections 4.9) 1. Which can be a pH buffer system? ❏ Na + + Cl - ❏ H 3 O + + OH - ❏ HF + F - ❏ CO 3 2- + PO 4 3- 2. Which recipe makes a good buffer? ❏ 1 mole CH 3 COOH + 0.5 mole NaOH ❏ 1 mole HCl + 0.5 mole NaOH ❏ 1 mole CH 3 COOH + 1 mole NaOH ❏ 1 mole HCl + 1 mole NaOH 3. What would be the buffering capacity of 2 mole CH 3 COOH + 1 mole NaOH? ❏ 3 mole ❏ 2 mole ❏ 1 mole ❏ 0.5 mole 4. What would be the buffering capacity of 2 mole CH 3 COOH + 2 mole CH 3 COONa? ❏ 4 mole ❏ 2 mole ❏ 1 mole ❏ 0 mole 5. At which point would the solution be a good buffer system? ❏ #1 ❏ #2 ❏ #3 ❏ #4 6. What would be the pH range of this buffer? ❏ 2-4 16

OCV Chemistry, Grade 12 University Preparation (SCH4U) Ottawa-Carleton Virtual Secondary School 2020-2021 Mr. Daniel Cho-En Lee ( daniel.cho-en.lee@ocdsb.ca ) ❏ 4-6 ❏ 6-8 ❏ 8-10 7. pK a of CH 3 COOH = 4.7. In a solution there is 1 mole of CH 3 COOH. To make a pH 5.0 buffer, moles of NaOH needed =... ❏ > 0.5 ❏ < 0.5 ❏ = 0.5 8. pK b of NH 3 = 4.7. In a solution there is 1 mole of NH 3 . To make a pH 9.0 buffer, moles of HCl needed =... ❏ > 0.5 ❏ < 0.5 ❏ < 0.5 17