Predicting Changes in Entropy

Predict the entropy change, ΔS.

• ΔS = +ve
• ΔS = -ve
• ΔS = 0
• ΔS = no change

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

Given the change of phase:

CO₂(g) —> CO₂(s)

As CO₂(g) changes to CO₂(s), the entropy of the system

• decreases

• increases

• remains the same

Which phase change represents a decrease in entropy?

• solid to liquid

• gas to liquid

• liquid to gas

• solid to gas

Which involves an increase in entropy? (if needed, select more than one answer)

• spraying an air freshener

• picking up apples off the ground

• dropping an egg on the floor

• arranging a deck of cards by suit

ΔS will be positive for the reaction

• 2H₂ (g) + O₂ (g) -> 2H₂O (g)

• 2NO₂ (g) -> N₂O₄ (g)

• BaF₂ (s) ->Ba²⁺ (aq) + 2F^- (aq)

• 2Hg (l) + O₂ (g) ->2HgO (s)

Tags

NGSS.HS-PS1-4

A reaction that is not spontaneous at low temperature can become spontaneous at high temperature if ΔH is __________ and ΔS is __________.

• +, +

• -, -

• +, -

• -, +

Entropy always increases when

• enthalpy decreases.
• temperature decreases.
• temperature increases.
• volume increases.

An increase in  numbers of moles from reactants to products (e.g. 3A  --> 4 B) would cause a decrease in entropy.

• True
• False

For the following reaction indicate if entropy is increased or decreased.    2N₂(g)  +  3 H₂(g)  ------->  2 NH₃(g)

• increase
• decrease

Tags

NGSS.HS-PS3-4

For the following reaction indicate if entropy is increased or decreased.     KClO₃(s)  ------>  KCl(s)  +  O₂(g) 

• increase
• decrease

Tags

NGSS.HS-PS3-4