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.
ScanSolve AI Answer
Here's how to solve the problem: Part (a): Calculate the heat evolved Step 1: Calculate the total volume of the solution. Total volume = Volume of HCl + Volume of NaOH Total volume = 50 cm^3 + 50 cm^3 = 100 cm^3 Step 2: Calculate the total mass of the solution. Mass (m) = Density × Total volume m = 1.0 g cm^-3 × 100 cm^3 = 100 g Step 3: Calculate the temperature change ( T). T = Final temperature - Initial temperature T = 34^ - 27^ = 7^ Since a change of 1^ is equal to a change of 1 K, T = 7 K. Step 4: Calculate the heat evolved (Q) using the formula Q = mc T. Q = 100 g × 4.2 J g^-1 K^-1 × 7 K Q = 2940 J The heat evolved is 2940 J. Part (b): Calculate the enthalpy change per mole of water formed Step 1: Write the balanced chemical equation for the neutralization reaction. HCl(aq) + NaOH(aq) NaCl(aq) + H_2O(l) From the equation, 1 mole of HCl reacts with 1 mole of NaOH to produce 1 mole of H_2O. Step 2: Calculate the moles of reactants. Volume of HCl = 50 cm^3 = 0.050 dm^3 Moles of HCl = Concentration × Volume Moles of HCl = 1.0 mol dm^-3 × 0.050 dm^3 = 0.050 mol Volume of NaOH = 50 cm^3 = 0.050 dm^3 Moles of NaOH = Concentration × Volume Moles of NaOH = 1.0 mol dm^-3 × 0.050 dm^3 = 0.050 mol Since the moles of HCl and NaOH are equal and react in a 1:1 ratio, 0.050 mol of water is formed. Step 3: Calculate the enthalpy change per mole of water formed ( H_neut). The heat evolved (Q) is 2940 J. Since heat is evolved, the enthalpy change is negative. H_neut = -(Q)/(Moles of water formed) H_neut = -2940 J0.050 mol H_neut = -58800 J mol^-1 Step 4: Convert the enthalpy change to kilojoules per mole. H_neut = -58800 J mol^-1 × 1 kJ1000 J H_neut = -58.8 kJ mol^-1 The enthalpy change per mole of water formed is -58.8 kJ mol^-1.