2015各区二模计算题汇总(国外英文资料).docVIP

2015各区二模计算题汇总 The problems are summarized in each section The mixture of 7.8 grams of zinc and copper and 49.0 g dilute sulphuric acid are exactly the right reaction, and the amount of material produced by hydrogen is shown in the diagram. (1) to calculate the quality of zinc in the sample (20) (according to the formula of the chemical equation); (2) the mass fraction of the solute in the solution after the reaction is (21) Accurate to 0.1%). The answer So you have zinc in your sample, and you have zinc sulfate 1 minute, 1 mole of 1 mole X y 0.1 mole 1: x = 1: o. 1 x = 0.1 mol 1: y = 1:0.1, y = 0.1 mol M (Zn) = 0.1 * 65 = 6.5 g 1 M (ZnSO4) = 0.1 * 161 = 16.1 g The solutions mass = 6.5 + 49.0-0.2 = 55.3 g ZnSO4 % = 16.1/55.3 29.1% (4) the laboratory commonly used chongming two mode, 50 】 【 limestone and dilute hydrochloric acid producing CO2, a certain interest groups for the determination of the limestone samples (impurity does not dissolve in water, does not react with acid) in the mass fraction of calcium carbonate, as shown in the experiments. Add 100 g dilute hydrochloric acid Perfect reaction Add 110.8 g of water Its an unsaturated solution A 25g sample of limestone B The total mass of C mixture is 227g Calculate (I) the amount of carbon dioxide produced by the reaction is (7) moles. (II) the quality score of calcium carbonate in limestone samples? (according to the formula of the chemical equation) (8). The answer (7) 0.2 moles. (the mass produced for CO2 is 25g + 100g + 110.8 g - 227g = 8.8 g) (4) the amount of CaCO3 in the limestone sample is xmol CaCO3 + 2HCl CaCl2 + H2O + CO2 arrow 1 1 mole per mole X 0.2 1: X = 1:0.2:1 X is equal to 0.2 moles of 1 The quality of calcium carbonate in the sample is 20g and the quality score is 80% A: the mass fraction of calcium carbonate in limestone is 80% Fe2O3, fengxian two mode, 46 】 【 CuO solids mixing powder a, g, under the condition of heating with adequate CO reduction, metal mixture is 2.41 g, the generated CO2 g