a) dissolving sugar in water to form a mixture of sugar and water
Explanation:
exothermic reaction is reaction in which is heat is released during the reaction and endothermic reaction is a reaction in which heat is needed or required for the reaction to take place
all the options excluding option A) is exothermic as during the process of formation of bonds in oxidation, heat is released. rusting too is a slow form of oxidation and thus an exothermic reaction.
dissolving sugar in water is not exothermic reaction because their is no heat released. the sugar molecules simply disperses in the water molecules and form a solution.
The heat required to completely melt the given substance, platinum, we just have to convert first the given mass in mole and multiply the answer to its molar heat of fusion.. Hf = mass x (1/molar mass) x molar heat of fusion Hf = (85.5 g) x (1 mole/195.08 g) x 4.70 kcal/mol Hf = 2.06 kcal
