Question

47.7 g chunk of ice at -58 Celsius is heated until it completely melt find the total amount of heat in joules for this process to occur. What is the total amount of energy needed overall in kilojoules (three sig figs)

Answer 1

Answer: The total amount of energy needed overall in kilojoules is, 21.8

Step-by-step explanation:

The conversions involved in this process are :

`(1):H_2O(s)(-58^0C)\rightarrow H_2O(s)(0^0C)\\\\(2):H_2O(s)(0^0C)\rightarrow H_2O(l)(0^0C)`

Now we have to calculate the enthalpy change.

`\Delta H=[m* c_(s)* (T_(final)-T_(initial))]+n* \Delta H_(fusion)`

where,

`\Delta H` = enthalpy change = ?

m = mass of ice = 47.7 g = 0.0477 kg (1kg=1000g)

`c_(s)` = specific heat of solid water =
`2.108kJ/kg^0C`

n = number of moles of water =
`\frac{\text{Mass of water}}{\text{Molar mass of water}}=(47.7g)/(18g/mole)=2.65mole`

`\Delta H_(fusion)` = enthalpy change for fusion = 6.01 kJ/mole

Now put all the given values in the above expression, we get

`\Delta H=[0.0477kg* 2.108kJ/kg^0C* (0-(-58))^0C]+2.65mole* 6.01kJ/mole`

`\Delta H=21.8kJ`

Therefore, the enthalpy change is, 21.8 kJ