Question

.  Classify each process as endothermic or exothermic.  What is the sign of delta-H for each process?  Explain your answers.   (a) gasoline burning in an engine.   (b) steam condensing on a mirror.    (c) water boiling in a pot.

Answer 1

See below

Step-by-step explanation:

(a) gasoline burning in an engine.

Exothermic, with a - ΔH. The C-H bonds in the gasoline hydrocarbons are being broken in an oxidation process and releasing their energy.

(b) steam condensing on a mirror.

Exothermic, with - ΔH. The hot steam is losing energy as it goes through a transition from gas to liquid.

(c) water boiling in a pot.

Endothermic, with + ΔH. The water is absorbing energy to go through a transition from liquid to gas, and beyond if over 100C.