NECO 2020 Chemistry Practical Solution Answer/Questions Expo
WELCOME TO AYOSTUFFS BEST EXAM EVER ===================================== KEEP REFRESH THIS PAGE IN EVERY 5MIN =================================== CHEMISTRY PRACTICE SOLUTION (1) Volume of pipette is 25.00cm³ Titrations |Rough| 1 | 2 | 3 Final Reading|23.00|21.50|21.40|21.50 Initial Reading|0.00|0.00|0.00|0.00 Vol. Of acid used|23.00|21.50|21.40|21.50 (1a) Vol of acid used VA = 21.50+21.40+21.50/3 = 21.47cm³ (1bi) Conc. Of A in g/dm³ = 3.65÷500/1000 = 7.3g/dm³ Conc. of A in mol/dm³ = gram conc/molar mass = 7.3/[1+35.5] = 7.3/36.5 =0.2mol/dm³ (1bii) Using CAVA/CBVB = nA/nB 0.2×21.47/CB×25.00 = 2/1 CB = 0.2×21.47/25.00×2 = 0.08588mol/dm³ (1biii) Molar mass of B = gram conc/molarity = 10.60/0.08588 =123.43g/mol (1biv) X2CO3 = 123 2[X] + 12 + 3[16] = 123 2x + 60 = 123 2x = 123 - 60 = 63 X = 63/2 = 31.5 (1bV) No of moles of X2CO3 = molarity × volume = 0.08588 × 25 = 2.147moles Mole ratio of X2CO3 to CO2 is 1:1 Therefore, No o...