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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Here are the solutions to the problems. b) Step 1: Calculate the mass of the solution. The volume of the solution is 95 cm^3. The density of the solution is 1 g/cm^3. Mass of solution (m) = Volume × Density m = 95 cm^3 × 1 g/cm^3 = 95 g Step 2: Calculate the temperature change. The initial temperature is 43.7^ C. The final temperature is 49.6^ C. T = Final temperature - Initial temperature T = 49.6^ C - 43.7^ C = 5.9^ C Since a change of 1^ C is equal to a change of 1 K, T = 5.9 K. Step 3: Calculate the heat absorbed by the solution. The specific heat capacity of the solution (c) is 4.2 J/g K. Q = mc T Q = 95 g × 4.2 J/g K × 5.9 K Q = 2354.1 J Since the temperature increased, the reaction is exothermic, meaning the reaction released this heat. So, Q_reaction = -Q_solution = -2354.1 J. Convert to kilojoules: Q_reaction = -2354.1 J × 1 kJ1000 J = -2.3541 kJ Step 4: Calculate the moles of copper deposited. The mass of copper deposited is 3.83 g. The molar mass of copper (Cu) is 63.5 g/mol. Moles of Cu (n) = MassMolar mass n = 3.83 g63.5 g/mol ≈ 0.06031 mol Step 5: Calculate the molar enthalpy change. H = Q_reactionn H = -2.3541 kJ0.06031 mol H ≈ -39.03 kJ/mol Rounding to three significant figures: -39.0 kJ/mol 21. The atomic numbers of nitrogen and fluorine are 7 and 9 respectively. a) Draw electron dot (+) and Cross (x) diagrams to illustrate bonding in the molecules of: (I) Nitrogen Nitrogen (N) has an atomic number of 7, so it has 5 valence electrons. In a nitrogen molecule (N_2), two nitrogen atoms share three pairs of electrons to form a triple covalent bond, and each nitrogen atom has one lone pair of electrons. N ××× N × × (II) Fluorine Fluorine (F) has an atomic number of 9, so it has 7 valence electrons. In a fluorine molecule (F_2), two fluorine atoms share one pair of electrons to form a single covalent bond, and each fluorine atom has three lone pairs of