This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.
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8. a) Isotopes are atoms of the same element that have the same number of protons (atomic number) but different numbers of neutrons (mass number). From the given data, the atomic number for element K is 6. The isotopes of element K are: ^12_6K, ^13_6K, ^14_6K b) To calculate the relative atomic mass of element A, we use the formula: Relative Atomic Mass = (Isotope mass × % abundance100) Step 1: Substitute the values for isotope A1. Contribution from A1 = 62.93 × (69.09)/(100) = 62.93 × 0.6909 = 43.471837 Step 2: Substitute the values for isotope A2. Contribution from A2 = 64.93 × (30.91)/(100) = 64.93 × 0.3091 = 20.069123 Step 3: Add the contributions to find the relative atomic mass. Relative Atomic Mass of A = 43.471837 + 20.069123 = 63.54096 Rounding to two decimal places: Relative Atomic Mass of A = 63.54 9. Step 1: Calculate the mass of carbon in 4.2 g of carbon (IV) oxide (CO_2). Molar mass of C = 12.0 g/mol Molar mass of CO_2 = 12.0 + (2 × 16.0) = 44.0 g/mol Mass of C = Mass of C in CO_2Molar mass of CO_2 × Mass of CO_2 Mass of C = (12.0)/(44.0) × 4.2 g = 0.2727 × 4.2 g ≈ 1.1454 g Step 2: Calculate the mass of hydrogen in 1.71 g of water (H_2O). Molar mass of H = 1.0 g/mol Molar mass of H_2O = (2 × 1.0) + 16.0 = 18.0 g/mol Mass of H = Mass of 2H in H_2OMolar mass of H_2O × Mass of H_2O Mass of H = (2 × 1.0)/(18.0) × 1.71 g = (2.0)/(18.0) × 1.71 g = 0.1111 × 1.71 g ≈ 0.1900 g Step 3: Calculate the moles of carbon and hydrogen. Moles of C = Mass of CMolar mass of C = 1.1454 g12.0 g/mol ≈ 0.09545 mol Moles of H = Mass of HMolar mass of H = 0.1900 g1.0 g/mol = 0.1900 mol Step 4: Determine the simplest whole-number ratio of moles. Divide by the smallest number of moles (0.09545 mol). For C: (0.09545)/(0.09545) = 1 For H: (0.1900)/(0.09545) ≈ 1.99 ≈ 2 The ratio of C:H is approximately 1:2. The empirical formula of the hydrocarbon is CH_2. 10. i) To obtain pure water from a mixture of water and common salt, the best method is distillation.