Calculate the amount of heat required to completely sublime 96.0 gg of solid dry ice (CO2)(CO2) at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 kJ/molkJ/mol. Express your answer in kilojoules.

The correct answer is 70.41 kJ ≅ 70.4 kJ

Explanation:

The heat required to sublimate the solid at its sublimation temperature is calculated by using the following formula:

heat = ΔHs x moles of substance

Where ΔHs is the heat of sublimation, which is known (32.3 kJ/mol).

So, we have to calculate the moles of substance. For this, we can divide the mass of substance by the molecular weight of substance (CO₂):

mass CO₂ = 96.0 g

molecular weight CO₂ = (12 g/mol x 1) + (16 g/mol x 2) = 44 g/mol

⇒ moles of CO₂ = mass CO₂/molecular weight CO₂ = (96.0 g)/(44 g/mol) = 2.18 moles

Finally, we use the first formula to calculate the heat:

heat = ΔHs x moles = 32.3 kJ/mol x 2.18 mol = 70.41 kJ ≅ 70.4 kJ

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.