To determine the molar enthalpy of reaction for the reaction of magnesium with hydrochloric acid, we can use the equation:
ΔH = q / n
where:
ΔH is the molar enthalpy of reaction (in kJ/mol)
q is the heat transferred (in J)
n is the number of moles of the limiting reactant in the reaction
First, let's calculate the heat transferred (q):
q = (mcalorimeter + macid) * C * ΔT
where:
mcalorimeter is the mass of the calorimeter (in g)
macid is the mass of the hydrochloric acid (in g)
C is the specific heat capacity of the solution (assumed to be 4.18 J/g°C)
ΔT is the change in temperature (in °C)
mcalorimeter = 3.53g
macid = 58.47g - 3.53g = 54.94g
C = 4.18 J/g°C
ΔT = 35°C - 21°C = 14°C
Substituting the values into the equation:
q = (3.53g + 54.94g) * 4.18 J/g°C * 14°C
q = 2409.14 J
Next, let's calculate the number of moles of magnesium used in the reaction:
n = m / M
where:
m is the mass of magnesium (in g)
M is the molar mass of magnesium (approximately 24.31 g/mol)
m = 0.17g
M = 24.31 g/mol
n = 0.17g / 24.31 g/mol
n ≈ 0.007 mol
Now, we can calculate the molar enthalpy of reaction (ΔH):
ΔH = q / n
ΔH = 2409.14 J / 0.007 mol
ΔH ≈ 344,162 J/mol
Converting J to kJ:
ΔH ≈ 344.162 kJ/mol
Therefore, the molar enthalpy of reaction for the reaction of magnesium with hydrochloric acid is approximately 344.162 kJ/mol.
Determine the molar enthalpy of reaction for the reaction of magnesium with hydrochloric acid.
Mass of calorimeter + hydrochloric acid is 58.47g
Mass of calorimeter is 3.53g
Initial temperature of the solution is 21 degrees celsius
Mass of the magnesium is 0.17g
Finial temperature of the solution is 35 degrees celsius
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