Stpm Sem 2 Chemistry Experiment 2013
Experiment 6 :Observation | KA2 | KA3 | Weight of test-tube + solid / g | | | Weight of empty test-tube / g | X1 | X2 | Weight of solid / g | | | Initial temperature of acid / °C | | | Final temperature of mixture / °C | θ1 | θ2 | Temperature change / °C | | |
Discussion :[In the experiment sheet, the is an error where questions in (c)(i) should be "the heat change involved the reactions involving KA2 and KA3] (c). i : q1 = mcθ1 ; q = (30.00)(4.18)( θ1) = q1 q2 = mcθ2 ; q = (30.00)(4.18)( θ2) = q2ii. mol of KA2 = mass / RMM ; mol of KA2 = x1 / 84 = a1 mol of KA3 = mass / RMM ; mol of KA3 = x2 / 106 = a2iii. HKA2 = q1 / a1 = - P kJ / mol HKA3 = q2 / a2 = +Q kJ / mol(d)KA2 + KA1 : Na2CO3(s) + 2 HCl (aq) → 2NaCl(aq) + H2O(l) + CO2 (g)KA3 + KA1 : NaHCO3 (s) + HCl (aq) → NaCl (aq) + H2O (l) + CO2 (g)(e) Energy Na2CO3 (s) + 2 HCl (aq) + H2O (l) + CO2 (g)HKA2
/ kJ H 2 x HKA3 2 NaCl (aq) + 2 H2O (l) + 2 CO2 (g) 2 NaHCO3 (s) + 2 HCl (aq)(f) Na2CO3(s) + 2 HCl (aq) → 2NaCl(aq) + H2O(l) + CO2 (g) [1] HKA2 = - P kJ NaHCO3 (s) + HCl (aq) → NaCl (aq) + H2O (l) + CO2 (g) [2] HKA3 = + Q kJ Reverse equation [1]2NaCl(aq) + H2O(l) + CO2 (g) → Na2CO3(s) + 2 HCl (aq) HKA2 = + P kJ / mol2 NaHCO3 → Na2CO3(s) + H2O +CO2 Hrxn = +P + 2(Q) kJ | Experiment 7 :Procedures -1. Set-up the apparatus as shown in the diagram below | 2. Using sand paper, both copper plates were brushed, and then dipped into propanone, followed by drying both plates using hair drier. |
3. Both plates were then weigh separately and were recorded as initial mass of anode and cathode in the table below.4. Both weighed plate were clipped using crocodile clips and the batteries were placed in the battery socket. After that, both plates were immersed in copper (II) solution and the stop watch was started to allow the apparatus to run for 30 minutes.5. the reading of ammeter was recorded. Then, both plates were taken out from the solution, and
Discussion :[In the experiment sheet, the is an error where questions in (c)(i) should be "the heat change involved the reactions involving KA2 and KA3] (c). i : q1 = mcθ1 ; q = (30.00)(4.18)( θ1) = q1 q2 = mcθ2 ; q = (30.00)(4.18)( θ2) = q2ii. mol of KA2 = mass / RMM ; mol of KA2 = x1 / 84 = a1 mol of KA3 = mass / RMM ; mol of KA3 = x2 / 106 = a2iii. HKA2 = q1 / a1 = - P kJ / mol HKA3 = q2 / a2 = +Q kJ / mol(d)KA2 + KA1 : Na2CO3(s) + 2 HCl (aq) → 2NaCl(aq) + H2O(l) + CO2 (g)KA3 + KA1 : NaHCO3 (s) + HCl (aq) → NaCl (aq) + H2O (l) + CO2 (g)(e) Energy Na2CO3 (s) + 2 HCl (aq) + H2O (l) + CO2 (g)HKA2
/ kJ H 2 x HKA3 2 NaCl (aq) + 2 H2O (l) + 2 CO2 (g) 2 NaHCO3 (s) + 2 HCl (aq)(f) Na2CO3(s) + 2 HCl (aq) → 2NaCl(aq) + H2O(l) + CO2 (g) [1] HKA2 = - P kJ NaHCO3 (s) + HCl (aq) → NaCl (aq) + H2O (l) + CO2 (g) [2] HKA3 = + Q kJ Reverse equation [1]2NaCl(aq) + H2O(l) + CO2 (g) → Na2CO3(s) + 2 HCl (aq) HKA2 = + P kJ / mol2 NaHCO3 → Na2CO3(s) + H2O +CO2 Hrxn = +P + 2(Q) kJ | Experiment 7 :Procedures -1. Set-up the apparatus as shown in the diagram below | 2. Using sand paper, both copper plates were brushed, and then dipped into propanone, followed by drying both plates using hair drier. |
3. Both plates were then weigh separately and were recorded as initial mass of anode and cathode in the table below.4. Both weighed plate were clipped using crocodile clips and the batteries were placed in the battery socket. After that, both plates were immersed in copper (II) solution and the stop watch was started to allow the apparatus to run for 30 minutes.5. the reading of ammeter was recorded. Then, both plates were taken out from the solution, and