Name ______

Hour ______

Heat of Fusion of Ice

Honors 9 Chemistry

Introduction: Any solid at its melting point requires a certain input of energy to melt. The energy absorbed by the solid is used to disrupt the crystal lattice structure of the solid and increases the disorder of the particles within the sold. The amount of energy required to change a unit mass of a solid to a liquid is the heat of fusion.

Purpose: To experimentally determine the heat of fusion of ice.

Materials:

  • Calorimeter (Styrofoam cup)
  • Thermometer
  • Balance
  • Water
  • Ice

Procedure:

  1. Mass the calorimeter on the balance, record mass on data table.
  2. Add 150 mL of water to calorimeter and mass again, record mass.
  3. Determine mass of the water
  4. Place thermometer in water, record initial temperature
  5. Add approximately 15 g of ice (about 5-6 ice cubes), to the water, mass and calculate the mass of ice.
  6. Record the temperature the moment the ice has completely melted.
  7. Calculate the change in temperature
  8. Repeat steps 1-7 two more times for a total of 3 trials
  9. Calculate the average of the three trials and record the data on the table
  10. Determine the heat of fusion for the ice using the averages.

DATA TABLE:

A / B / C / D / E / F / G / H
Mass of calorimeter / Mass of calorimeter and water / Mass of water / Mass of calorimeter and ice and water / Mass of ice / Initial temperature / Final temperature / Change in temperature

***Average of three trials goes below the dark black line

CALCULATE THE HEAT OF FUSION: (us the averages from above to calculate the heat of fusion)

Formula A:

(heat lost by the water in the calorimeter) = (original mass of water in calorimeter) x (change in temperature) x (specific heat capacity of water).

Symbol representation of formula A  Q = m x C x ∆T

Question #1) Calculate the heat needed to melt the ice (make sure to include units in your work and answer)

(Hint: the specific heat capacity of water or C = 4.184 J/g ̊C)

Formula B:

Heat (answer from question #1) ÷ mass of melted ice = heat of fusion of ice

Symbol representation of formula B  J/g = heat of fusion

Question #2) Calculate the heat of fusion of ice(make sure to include units in your work and answer)

Formula C

Percent error = Value accepted – Value experimentalx 100%

Value accepted

Hints: Value accepted is the value given in your notes. Value experimental is the value you calculated in question #2. The lines on the side of the formula are absolute values. No negative numbers

Question #3) Calculate the percent error for the heat of fusion(make sure to include units in your work and answer)

Question #4) How did the value you obtained for the heat of fusion of ice compare to the accepted value for the heat of fusion of ice. What might be some reasons for the difference between the two answers?

Question #5) Do you think the heat of vaporization is greater than or less than the heat of fusion? Explain your answer.