Question

In the stranger-than-fiction category, consider the following dissolutions, then answer the questions. Remember that isopropanol (IPA, rubbing alcohol) is miscible with water. 9 parts IPA + 1 part water ® 90% IPA in water (gets a little colder) 1 part IPA + 9 parts water ® 10% IPA in water (gets a little warmer) Isn't chemistry strange.

Why this happens is complicated, so let's just focus on what happens. a) Is mixing IPA with water endothermic or exothermic? Be complete in your answer.

b) Do you think there is a ratio of IPA and water you can mix together that would get neither hot nor cold (called a thermoneutral reaction)? Explain

c) So, what is the likely most significant factor in IPA and water mixing together? Explain

Answer 1