Exothermic & Endothermic Processes Notes

University:
High School
Course:
High School Chemistry
Academic year:

2025
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306

Pages:

2
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Exothermic & Endothermic Processes Energy & Chemical Reactions ● All chemical reactions involve energy ○ Energy is used or released when bonds break in reactants and again when bonds form in products ● Exothermic reactions ○ Take less energy to break bonds in the reactants than is released when new bonds form in the products ○ Overall release of energy ● Endothermic reactions ○ Take more energy to break bonds in the reactants than is released when new bonds form in the products ○ Overall input of energy Exothermic Reactions ● Exothermic - means “releasing heat” ○ General equation for an exothermic reaction: ■ Reactants → Products + Energy ● Endothermic - means “taking heat” ○ Endothermic reactions need an input of energy to work ■ Energy must be constantly added because not enough energy is released when the products form to break more bonds in the reactants - General equation for endothermic reactions: - Reactants + Energy → Products Endothermic Reactions ● The temperature of the products in endothermic reactions is typically lower than the temperature of the reactants ○ The drop in temperature might even be enough to cause liquids to freeze ■ This is how cold packs work ● Squeezing the pack breaks the inner bag of water which allows it to mix with the other chemicals to create an endothermic reaction ○ Photosynthesis is also an endothermic process