Entropy

What is the symbol for entropy?

• H

• G

• S

• E

Entropy is a measure of

• accuracy

• precision

• the disorder of a system

• the attraction of a nucleus for an electron

Which of these processes represents a decrease in entropy?

• sublimation of CO₂

• boiling water

• condensation of steam on cold glass

• NaCl dissolving in water

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

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 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)

Systems in nature tend to undergo changes toward

• lower energy and less disorder

• lower energy and more disorder

• higher energy and less disorder

• higher energy and more disorder

Which sample has the lowest entropy?

• 1 mole of KNO₃(l)

• 1 mole of KNO₃(s)

• 1 mole of H₂O(l)

• 1 mole of H₂O(g)

Tags

NGSS.HS-PS3-4

Entropy increases from solid, liquid to gas. Why?

• Molecular disorder increases

• Molecules increase in number from solid to gas

• Molecules are heavier in solid

• Molecules are more reactive

Tags

NGSS.HS-PS3-4

Which sample has the lowest entropy?

• 1 mole of HNO₃(aq)

• 1 mole of KNO₃(s)

• 1 mole of H₂O(l)

• 1 mole of N₂O(g)

Tags

NGSS.HS-PS3-4