If 60 cm3 of a saturated solution of KNO3 contains 15.6 g of the salt at 35 °C, calculate the solubility of KNO3 in mol dm-3 at that temperature. [K = 39.0, O = 16.0, N = 14.0]

Step 1: Calculate the molar mass of KNO_3. M(KNO_3) = M(K) + M(N) + 3 × M(O) M(KNO_3) = 39.0 + 14.0 + (3 × 16.0) = 39.0 + 14.0 + 48.0 = 101.0 g/mol Step 2: Calculate the number of moles of KNO_3. Moles of KNO_3 = Mass of KNO_3Molar mass of KNO_3 Moles of KNO_3 = 15.6 g101.0 g/mol ≈ 0.15446 mol Step 3: Convert the volume of the solution from cm^3 to dm^3. 1 dm^3 = 1000 cm^3 Volume = 60 cm^3 = (60)/(1000) dm^3 = 0.060 dm^3 Step 4: Calculate the solubility of KNO_3 in mol dm^-3. Solubility = Moles of KNO_3Volume of solution Solubility = 0.15446 mol0.060 dm^3 ≈ 2.57 mol dm^-3 b) (ii) The solubility of KNO_3 is 2.57 mol dm^-3. Step 5: Outline the preparation of PbCl_2(s) from Pb(NO_3)_2 and a mineral acid. c) (i) To prepare PbCl_2(s), mix an aqueous solution of lead(II) nitrate (Pb(NO_3)_2) with a mineral acid containing chloride ions, such as hydrochloric acid (HCl). Lead(II) chloride will precipitate out as a solid. Filter the precipitate, wash it with distilled water, and then dry it. Step 6: Write an equation for the reaction in 2(c)(i). c) (ii) Pb(NO_3)_2(aq) + 2HCl(aq) PbCl_2(s) + 2HNO_3(aq) Step 7: Give the reason for copper's electron configuration. d) (i) The electron configuration of copper is 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^1 because a completely filled d-subshell (3d^10) is more stable than a partially filled d-subshell (3d^9). One electron from the 4s orbital is promoted to the 3d orbital to achieve this greater stability. Step 8: Mention the two oxidation states of iron in its chlorides. d) (ii) The two oxidation states of iron in its chlorides are +2 (in FeCl_2) and +3 (in FeCl_3). Step 9: Name one chemical process in which iron is used as a catalyst. d) (iii) Iron is used as a catalyst in the Haber process (for the synthesis of ammonia). Send me the next one 📸