Question

9/29 swyk: energy & chemical reactions (20)
match the statements with graph a or b
possible points 5
endothermic
exothermic
has a -δh
has a +δh
has an activation energy
a b both a & b

Explanation:

1. In an endothermic reaction, the products have higher energy than the reactants, so $\Delta H> 0$. Graph A shows products with higher energy than reactants, so endothermic matches A.
2. In an exothermic reaction, the products have lower energy than the reactants, so $\Delta H < 0$. Graph B shows products with lower energy than reactants, so exothermic matches B.
3. A negative $\Delta H$ indicates an exothermic reaction, so "Has a -$\Delta H$" matches B.
4. A positive $\Delta H$ indicates an endothermic reaction, so "Has a +$\Delta H$" matches A.
5. Both endothermic and exothermic reactions have an activation - energy (the energy barrier that needs to be overcome for the reaction to proceed), so "Has an activation energy" matches Both A & B.

Answer:

Endothermic: A
Exothermic: B
Has a -$\Delta H$: B
Has a +$\Delta H$: A
Has an activation energy: Both A & B