How many kilojoules of energy are needed to convert 104 g of ice at -14.6 to water at 25.8°C? (The specific heat of ice at -14.6 is 2.01 J/g°C.)

User Icon for DrBob222 DrBob222 answered
11 years ago

q1 = head needed to raise T of solid ice at -14.6 (is that C?) to zero.

q1 = mass ice x specific heat ice x (Tfinal-Tinitial)

q2 = heat needed to melt ice.
q2 = mass ice x heat fusion

q3 = heat needed to raise T of water from zero C to 25.8 C.
q3 = mass H2O x specific heat H2O x (Tfinal-Tinitial)

Total Q = q1 + q2 + q3

User Icon for just need set up just need set up answered
11 years ago

Thank you Dr Bob

User Icon for Explain Bot Explain Bot answered
11 months ago

To answer this question, we need to calculate the energy required to raise the temperature of the ice from -14.6°C to 0°C and then convert it from ice at 0°C to water at 0°C, and finally raise the temperature of water from 0°C to 25.8°C.

Step 1: Calculate the energy required to heat the ice from -14.6°C to 0°C.
The specific heat capacity (C) of ice at -14.6°C is given as 2.01 J/g°C. The mass (m) of ice is 104 g. The temperature change (ΔT) is 0°C - (-14.6°C) = 14.6°C.

The energy (Q) required to heat the ice is calculated using the formula:
Q = m * C * ΔT

Substituting the given values, we get:
Q = 104 g * 2.01 J/g°C * 14.6°C
Q = 2996.64 J

Therefore, it takes 2996.64 J of energy to heat the ice from -14.6°C to 0°C.

Step 2: Calculate the energy required to melt the ice from 0°C to water at 0°C.
The heat of fusion (ΔHfus) for ice is 334 J/g. Since all the ice is expected to melt at 0°C, we can directly calculate the energy required.

The energy (Q) required to melt the ice is calculated using the formula:
Q = m * ΔHfus

Substituting the given values, we get:
Q = 104 g * 334 J/g
Q = 34736 J

Therefore, it takes 34736 J of energy to melt 104 g of ice at 0°C to water at 0°C.

Step 3: Calculate the energy required to heat the water from 0°C to 25.8°C.
The specific heat capacity (C) of water is generally considered to be 4.18 J/g°C. The mass (m) of the water is 104 g. The temperature change (ΔT) is 25.8°C - 0°C = 25.8°C.

The energy (Q) required to heat the water is calculated using the formula:
Q = m * C * ΔT

Substituting the given values, we get:
Q = 104 g * 4.18 J/g°C * 25.8°C
Q = 10919.88 J

Therefore, it takes 10919.88 J of energy to heat 104 g of water from 0°C to 25.8°C.

Step 4: Calculate the total energy required.
To find the total energy required, we add up the energies calculated in steps 1, 2, and 3:
Total energy = Energy to heat ice + Energy to melt ice + Energy to heat water
Total energy = 2996.64 J + 34736 J + 10919.88 J
Total energy = 48652.52 J

Therefore, it takes 48652.52 J (or 48.65 kJ) of energy to convert 104 g of ice at -14.6°C to water at 25.8°C.