90 grams of lead (II) nitrate (Pb(NO3)2) are put into 100 grams of water and stirred. The final mixture has a temperature of 20∘C. About how many grams of lead (II) nitrate dissolved?

Which best describes the activation energy of a chemical reaction? a. the combined energy of all the reactants b. the amount of energy required for a reaction to occur c. the difference in energy between products and reactants d. the potential energy stored in the bonds of reactants and products