WAEC - Chemistry (2019 - No. 25)
If the value of ΔH is positive for a reaction, it means that the reaction is?
exothermic
endothermic
spontaneous
slow
توضیح
- 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.