The enthalpy change for melting ice is called the entlaphy of fusion. Its value is 6.02 kj/mol. This means for every mole of ice we melt we must apply 6.02 kj of heat. We can calculate the heat needed with the following equation:
Q = N x ΔH
where:
Q = heat
N = moles
ΔH = enthalpy
In this problem we would like to calculate the heat needed to melt 35 grams of ice at 0 °C. This problem can be broken into three steps:
1. Calculate moles of water
2. multiply by the enthalpy of fusion
3. Convert kJ to J.
Step 1 : Calculate moles of water
[tex][ 75g ] x (\frac{1 mol}{18.02g} ) =[/tex]
Step 2 : Multiply by enthalpy of fusion
Q = N × ΔH = [ Step 1 Answer ] × 6.02 =
Step 3 : Convert kJ to J
[tex][ Step 2 Answer ] x (\frac{1000j}{1kJ} ) =[/tex]
Finally rounding to 2 sig figs (since 34°C has two sig figs) we get
Q Would Equal ____
