5. The heat of fusion of ice is 333.5J/g. The entropy change for the water when freezing 5.0 g of water at 0°C and 1 atm pressure is:

(a) 6.1 J/K

(b) 1.2 J/K

(C) OJ/K

(d) -1.2 J/K

(e) -6.1 J/K

(e) -6.1 J/K

Explanation:

Step 1: Given data

Step 2: Calculate the heat (Qfreezing) required to freeze 5.0 g of water

We will use the following expression.

Qfreezing = -ΔH°fus × m

Qfreezing = -333.5 J/g × 5.0 g = -1.7 × 10³ J

Step 3: Calculate the entropy change (ΔS°) at 0 °C (273.15 K) and 1 atm

We will use the following expression.

ΔS° = Qfreezing/T

ΔS° = -1.7 × 10³ J/273.15 K = -6.1 J/K

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.