Final answer:
The amount of energy needed to vaporize diethyl ether can be calculated using the equation Q = m * ΔH_vap. In this case, the amount of energy needed is approximately B) 26.7 kJ.
Step-by-step explanation:
The amount of energy needed to vaporize a substance can be calculated using the equation Q = m * ΔH_vap, where Q is the amount of heat energy, m is the mass of the substance, and ΔH_vap is the enthalpy of vaporization. In this case, the mass of diethyl ether is 75.0 g. To convert this to moles, we can divide the mass by the molar mass of diethyl ether (74.12 g/mol). This gives us approximately 1.01 moles.
Using the equation Q = m * ΔH_vap, we can calculate the amount of energy needed as follows:
Q = 1.01 moles * 26.5 kJ/mol = 26.7 kJ
Therefore, the amount of energy needed to vaporize 75.0 g of diethyl ether at its boiling point is approximately 26.7 kJ. Therefore, the correct answer is option b. 26.8 kJ.