195k views
0 votes
When sodium thiosulfate pentahydrate dissolves in water in a beaker, the beaker becomes cold. Why?A.) This solute was cold when it was placed into the water.B.) Dissolving this solute is an exothermic process.C.) Dissolving this solute reaches a cold equilibrium point.D.) Dissolving this solute is an endothermic process.

1 Answer

4 votes

When we make a mixture, the molecules and bonds present in each of the substances can exert attraction or repulsion and can absorb or release energy. This energy is evidenced by an increase or decrease in temperature.

When the mixture releases energy, the temperature will increase and is called exothermic. When the mixture absorbs energy, the temperature will decrease and is called endothermic.

Therefore, if the beaker becomes cold it means that the mixture of these two compounds is endothermic.

Answer: D.) Dissolving this solute is an endothermic process.

User Montdidier
by
6.6k points