Ashley Olsen and her twin sister Mary-Kate Olsen were professional actors before they could speak. A TV executive held the twins in his arms when they were three or maybe nine months old (accounts vary), and neither girl cried. On the basis of this audition, the Olsen twins landed the shared role of baby Michelle on Full House, when they weren't even toddlers. They were nine when the show finally ended.
Recall the relationship between the forward and reverse reaction rates when a reaction is at equilibrium. In a chemical equilibrium, the forward and reverse reactions occur at equal rates, and the concentrations of products and reactants remain constant.
Most chemical reactions involve the breaking and formation of chemical bonds. It takes energy to break a chemical bond but energy is released when chemical bonds are formed. If more energy is released than consumed, then the chemical reaction evolves heat and is said to be exothermic. On the other hand if the reaction consumes more energy than it releases then the reaction absorbs heat and is said to be endothermic. Most reactions are exothermic. The amount of heat generated by a reaction can be quantified. The quantity that specifies the amount of heat is known as the enthalpy . If is positive then the reaction is endothermic and if it is negative the reaction is exothermic.