Question

Consider the combustion of liquid c₅h₈ in oxygen gas to produce carbon dioxide gas and water vapor. In an experiment, 0.1063 g of c₅h₈ is combusted to produce enough heat to raise the temperature of 150.0 g of water by 7.620 °C. If -4782 J of heat was produced from the combustion of 0.001561 moles of c₅h₈, what is the enthalpy change (in kJ/mol) for the combustion of c₅h₈?

Answer 1

The enthalpy change for the combustion of liquid C₅H₈, given that -4782 J of heat was produced from the combustion of 0.001561 moles, is approximately -3063 kJ/mol.

Step-by-step explanation:

The student is asking about the enthalpy change for the combustion of C₅H₈, based on experimental data. Given that 0.1063 g of C₅H₈ is combusted to raise the temperature of 150.0 g of water by 7.620 °C and -4782 J of heat was produced from the combustion of 0.001561 moles of C₅H₈, the enthalpy change can be calculated by dividing the total energy change by the number of moles. It's important to convert the energy from joules to kilojoules before dividing by the number of moles to get the enthalpy change in kJ/mol.

To calculate the enthalpy change per mole, we use the formula:

∆H (kJ/mol) = (Q/J) / (n/moles)

Where Q is the heat energy in joules, and n is the number of moles of C₅H₈. We have Q = -4782 J (or -4.782 kJ) and n = 0.001561 moles.

Thus, the enthalpy change for the combustion of C₅H₈ is:

∆H = (-4.782 kJ) / 0.001561 moles ≈ -3063 kJ/mol