a 35.6g sample of ethanol (c2h5oh) is burned a bomb calorimeter, according to the following reaction. If the temperature rose from 35.0 to 76.0c and the heat capacity of the calorimeter is 23.3kj/c what is the value of enthalpyH reaction? the molar mass of ethanol is 46.07g/mol.
c2h5oh+3o2reacts with 2c02+3h20
To find the enthalpy change (ΔH) of the reaction, we can use the equation:
ΔH = q / n
where ΔH is the enthalpy change, q is the heat gained or lost by the system, and n is the number of moles of the substance involved in the reaction.
First, let's calculate the heat gained or lost by the system (q). We can use the equation:
q = mcΔT
where q is the heat gained or lost, m is the mass, c is the heat capacity of the calorimeter, and ΔT is the change in temperature.
Given:
Mass of ethanol = 35.6 g
Temperature change = 76.0 °C - 35.0 °C = 41.0 °C
Heat capacity of the calorimeter = 23.3 kJ/°C
Converting the heat capacity to joules:
23.3 kJ = 23.3 × 1000 = 23,300 J
Calculating q:
q = (35.6 g) × (23,300 J/°C) × (41.0 °C)
q = 34,324,040 J
Next, we need to calculate the number of moles of ethanol (n). We can use the equation:
n = m / M
where n is the number of moles, m is the mass, and M is the molar mass.
Given:
Molar mass of ethanol (C2H5OH) = 46.07 g/mol
Mass of ethanol = 35.6 g
Calculating n:
n = (35.6 g) / (46.07 g/mol)
n ≈ 0.772 mol
Finally, we can calculate the value of ΔH by substituting the values q = 34,324,040 J and n = 0.772 mol into the equation:
ΔH = q / n
ΔH = 34,324,040 J / 0.772 mol
Calculating ΔH:
ΔH ≈ 44,535,142.5 J/mol
Therefore, the value of the enthalpy change (ΔH) for the given reaction is approximately 44,535,142.5 J/mol.