#Chem 162-2008 homework 10th week

#Chem 162-2008 homework 10th week - Chem 162-2008 Hill...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
th Week Disorder, Entropy, and Spontaneous Change 19. For each of the following reactions, indicate whether you would expect the entropy of the system to increase or decrease. If you cannot tell just by inspecting the equation, explain why. (a) CH 3 OH(l) → CH 3 OH(g) Increase; going from a liquid to a gas increases entropy. (b) N 2 O 4 (g) → 2NO 2 (g) Increase; going from one mole of a gas to two moles of gas increases entropy. (c) CO(g) + H 2 O(g) → CO 2 (g) + H 2 (g) No change; going from two moles of gas to two moles of gas results in no change in entropy. Also, one molecule of gas becomes larger (CO → CO 2 ), while the other becomes smaller (H 2 O → H 2 ) cancels out the effect of increasing the size of the molecules. (d) 2KClO 3 (s) → 2KCl(s) + 3 O 2 (g) Increase; 3 moles of gas form. (e) CH 3 COOH(l) → CH 3 COOH(s) Decrease; going from a liquid to a solid decreases the entropy. (f) N 2 (g) + O 2 (g) → 2 NO(g) No change; going from two moles of gas to two moles of gas is no change in entropy. (g) N 2 H 4 (l) → N 2 (g) + 2H 2 (g) Increase; forming three moles of gas. (h) 2NH 3 (g) + H 2 SO 4 (aq) → (NH 4 ) 2 SO 4 (aq) Decrease; going from one mole of gas to zero moles of gas. 21. In the manner used to describe Figure 17.3, describe the situation if the two liquids are water and octane (C 8 H 18 , a component of gasoline). That is, what would you expect to find for the final condition of the mixture? Explain. I would expect there to be some mixing of the water and octane, due to an increase in entropy. However, due to the very unfavorable enthalpy of solution, I would expect the mixing to be very minimal. 23. Three possible completions of a statement are given. Explain what is wrong with each one, and then complete the statement correctly. For a process to occur spontaneously, (a) the entropy of the system must increase. If the entropy of the system increases, but the entropy of the surroundings decreases at least by the amount of the system increase, then the entropy of the universe will either not change or will decrease, resulting in a non-spontaneous process. the entropy of the universe must increase. (b) the entropy of the surroundings must increase. If the entropy of the surroundings increases, but the entropy of the system decreases at least by the amount of the surroundings increase, then the entropy of the universe will either not change or will decrease, resulting in a non-spontaneous process. the entropy of the universe must increase. (c) both the entropy of the system and of the surroundings must increase. They both don’t have to increase.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 5

#Chem 162-2008 homework 10th week - Chem 162-2008 Hill...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online