what is the molar change in enthalpy when 100 g of ice is heated from -18.2C to -7.2C?(C=37.4 J/K*mol)
heat/mole= mass/molmass*C*(-7.2+18.2) J
5.1 L
2,283.3J
To calculate the molar change in enthalpy, we need to know the heat capacity (C) of ice. In this case, the heat capacity of ice is given as 37.4 J/K*mol.
First, we need to calculate the amount of heat required to raise the temperature of 100 g of ice. This can be done using the formula:
Q = m * C * ΔT
where Q is the amount of heat, m is the mass, C is the specific heat capacity, and ΔT is the change in temperature.
In this case, the mass (m) is 100 g, the specific heat capacity (C) is 37.4 J/K*mol, and the change in temperature (ΔT) is (-7.2°C - (-18.2°C)) = 11°C.
Now, let's calculate the amount of heat required:
Q = 100 g * 37.4 J/K*mol * 11°C
We need to convert the mass from grams to moles by dividing by the molar mass of ice, which is 18.015 g/mol. This conversion factor is necessary to obtain the molar change in enthalpy.
moles of ice = 100 g / 18.015 g/mol
Finally, we can calculate the molar change in enthalpy using the formula:
ΔH = Q / moles of ice
Now, let's proceed with the calculations to find the molar change in enthalpy.