You place 35 g of this cryoprotectant at 22°C in contact with a cold plate that is maintained at the boiling temperature of liquid nitrogen (77 K). The cryoprotectant is thermally insulated from everything but the cold plate. Use the values in the table to determine how much heat will be transferred from the cryoprotectant as it reaches thermal equilibrium with the cold plate.
(a) 1.5 × 10⁴ J;

(b) 2.9 × 10⁴ J;

(c) 3.4 × 10⁴ J;

(d) 4.4 × 10⁴ J.

In cryopreservation, biological materials are cooled to a very low temperature to slow down chemical reactions that might damage the cells or tissues. It is important to prevent the materials from forming ice crystals during freezing. One method for preventing ice formation is to place the material in a protective solution called a cryoprotectant. Stated values of the thermal properties of one cryoprotectant are listed here:

Melting point .......................................................... -20‑C

Latent heat of fusion .............................................. 2.80 × 10⁵ J/kg

Specific heat (liquid) ............................................... 4.5 × 10³ J/kg ∙ K

Specific heat (solid) ................................................. 2.0 × 10³ J/kg ∙ K

Thermal conductivity (liquid) .................................... 1.2 W/m ∙ K

Thermal conductivity (solid) ..................................... 2.5 W/m ∙ K