Answer:
12.928 kJ
Step-by-step explanation:
To calculate the energy required to melt a substance, we use the formula:
Q = m * ΔHfus
where Q is the energy required, m is the mass of the substance, and ΔHfus is the heat of fusion, which is the amount of energy required to melt one gram of the substance.
For methane, the heat of fusion is 0.202 kJ/g. We can calculate the amount of energy required to melt 64g of methane as follows:
Q = m * ΔHfus
Q = 64g * 0.202 kJ/g
Q = 12.928 kJ
Therefore, it takes approximately 12.928 kJ of energy to melt 64g of methane at 90K.