In an experiment to determine the specific latent heat of fusion of ice, warm water and ice were mixed in a copper calorimeter - Leaving Cert Physics - Question 3 - 2017

To ensure that the temperature of all the added ice was at 0.0 °C, the ice must be crushed into small pieces and kept in an insulated container before being added to the calorimeter. This approach allows the ice to maintain thermal equilibrium and ensures that it remains at the freezing point before it is introduced to the warmer water. Alternatively, melting the ice partially by placing it in a controlled environment can achieve the same result.

1. A thermal insulator, such as Styrofoam or fiberglass, could be wrapped around the calorimeter to reduce heat loss.
2. Using a lid on the calorimeter can also help to minimize heat exchange with the surroundings.

To calculate the specific latent heat of fusion of ice, we can use the formula:

$m_w c_w (T_f - T_i) + m_i L = m_{wc} c_{wc} (T_f - T_i)$

Where:

• $m_w$ = mass of water after melting ice, $= 48.4$ g
• $c_w$ = specific heat capacity of water, $= 4180$ J kg⁻¹ K⁻¹
• $T_f$ = final temperature, $= 12.0$ °C
• $T_i$ = initial temperature, $= 0.0$ °C
• $m_i$ = mass of added ice, $= 8.2$ g
• $L$ = specific latent heat of fusion

The rearranged equation to calculate L is:

$(8.2) (1/1000)(4180)(12) = (48.4)(4180)(14.5) + (61.8)(390)(14.5)$

The final computation yields:

$L = 3.5 imes 10^5 ext{ J kg}^{-1}$

1. The thermometer should have a small heat capacity to ensure it does not significantly alter the temperature of the calorimeter system itself during the measurement.
2. It must be graduated to 0.1 °C to provide precise temperature readings, allowing for accurate calorimetry results.