How much energy is required to melt these quantities of ice?
a. 56 g
b. 56 mol

The enthalpy is the amount of energy required to change from solid to liquid.

The molar enthalpy of fusion (kJ/mol) is 6.01 kJ/mol.

We can answer B first, since solving for A would require us to find moles, which takes more time.

q = H*n
q = 6.01*56
q = 336.56 kJ

On to a.

Since we know the molar enthalpy of fusion, we need to solve for the number of moles in 56 grams of ice.

n = 56/(16.00 + 2(1.008))
n = 3.108 mol

Now we can solve.

q = H * n
q = 6.01 * 3.108
q = 18.7 kJ

Answers:
a. 18.7 kJ
b. 336.56 kJ

Let me know if you'd like me to explain anything I did here.

-T.B.

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.