If the value of ΔH is positive for a reaction, it means that the reaction is?

A.

exothermic

B.

endothermic

C.

spontaneous

D.

slow

Correct answer is B

- Endothermic reactions are chemical reactions in which the reactants absorb heat energy from the surroundings to form products.

-  A system of reactants that absorbs heat from the surroundings in an endothermic reaction has a positive ΔH.

 examples of endothermic processes:

  • Melting ice cubes.
  • Melting solid salts.
  • Sublimation of dry ice into carbon dioxide gas.
  • Evaporating liquid water.