Entropy

Which represents a decrease in entropy?

• sublimation of CO₂

• boiling water

• condensation of steam on cold glass

• NaCl dissolving in water

The entropy will usually increase when

• a molecule is broken into two or more smaller molecules

• a reaction occurs that results in an increase in the number of moles of gas

• a solid changes to a liquid

• all of these

Which sample has the lowest entropy?

HINT - Look at the phase of each chemical....

• 1 mole of KNO₃(l)

• 1 mole of KNO₃(s)

• 1 mole of H₂O(l)

• 1 mole of H₂O(g)

Tags

NGSS.HS-PS1-3

Which phase change represents a decrease in entropy?

• solid to liquid

• gas to liquid

• liquid to gas

• solid to gas

Tags

NGSS.MS-PS1-4

Entropy always increases when

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

Tags

NGSS.HS-PS3-4

Entropy of a system increases when a reaction increases the number of particles.

• True

• False

When gases are produced, Entropy is ____________.

• Greater than zero

• Lesser than zero

• Equal to zero

• Entropy wiill not be equal to zero, so its either of the two.

Tags

NGSS.HS-PS3-4

What is the symbol for entropy?

• H

• G

• S

• E

Which of these reactions shows a DECREASE in entropy?

• CaCO₃(s) → CaO(s) + CO₂(g)

• 3O₂(g) → 2O₃(g)

• 2NH₃(g) → 3H₂(g) + N₂(g)

• C₆H₆(l) → C₆H₆(g)

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

Which reaction has a +ΔS ?

• AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq)

• H₂O(g) + CO₂(g) → H₂CO₃(aq)

• H₂(g) + I₂(g) → 2Hl(g)

• C₂H₂O₂(g) → 2CO(g) + H₂(g)