Question

Use standard enthalpies of formation to calculate the standard change in enthalpy for the melting of ice. (The ΔHf∘ for H₂ₓO(s) is -291.8 kJ/mol).

Use this value to calculate the mass of ice required to cool 320 ml of a beverage from room temperature (25.0 ∘c) to 0.0 ∘c. assume that the specific heat capacity and density of the beverage are the same as those of water.

Answer 1

To calculate the standard change in enthalpy for the melting of ice, we can use the enthalpy of formation for H₂ₓO(s) and the enthalpy of fusion of ice. By converting the volume of the beverage to mass using the density of water, we can then calculate the number of moles of ice required to cool the beverage.

Step-by-step explanation:

To calculate the standard change in enthalpy for the melting of ice, we can use the enthalpy of formation (ΔHf∘) for H₂ₓO(s), which is -291.8 kJ/mol. The enthalpy of fusion (AHfus) of ice at 0 °C is 6.0 kJ/mol [^1^]. The melting process of ice is endothermic, meaning it absorbs heat from its surroundings.

Using these values, we can now calculate the standard change in enthalpy for the melting of ice:

ΔH = n × AHfus

where n is the number of moles of ice. To find the mass of ice required to cool 320 mL of a beverage from room temperature to 0.0 °C, we need to convert the volume to mass using the density of water (1 g/mL), and then calculate the number of moles of ice:

mass of ice = volume of beverage × density of water

moles of ice = mass of ice / molar mass of ice