19. salt a and salt b were each dissolved in separate
beakers of water at 21°c. the temperature of the
salt a solution decreased, and the temperature of
the salt b solution increased.

Question:

Salt A and salt B were each dissolved in separate beakers of water at 21°C. The temperature of the salt A solution decreased, and the temperature of the salt B solution increased. Based on these results, which conclusion is correct?            

1) The water gained energy from both salt A and salt B.                         2) The water lost energy to both salt A and salt B.            3) The water gained energy from salt A and lost energy to salt B.          4) The water lost energy to salt A and gained energy from salt B.  

Answer:

"The water lost energy to salt A and gained energy from salt B" is correct

Explanation:

It takes just somewhat greater energy to distinct the ions from one another than is unconfined from the water molecules adjacent the ions. This means just somewhat additional or extra energy must be put into the solution than is unconfined back into the solution. Therefore dissolving table salt in water leads to endothermic reaction. The dissolving salt into the water is an endothermic. It also implies, when the salt when dissolved in the water the temperature of the solution now is lower than earlier.  

conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.