Entropy Review

What is a Spontaneous Change?

• a change that occurs by itself

• a change that needs a push

Entropy is a state function

• False

• True

In an exothermic reaction, heat is ...

• taken in or absorbed
• given out or released

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

Entropy increases from solid, liquid to gas. Why?

• Molecular disorder increases
• Molecular randomness decreases
• Molecules are more energetic
• Molecules are more reactive

Tags

NGSS.MS-PS1-4

What is the symbol for entropy?

• H

• G

• S

• E

Which of these have a DECREASE in entropy?

• CaCO₃(s) → CaO(s) + CO₂(g)

• 2NO₂(g) → N₂O₄(g)

• 2NH₃(g) → 3H₂(g) + N₂(g)

• C₆H₆(l) → C₆H₆(g)

Tags

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

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

• increase
• decrease

Which of the following would have the highest entropy?

• A cold solid

• A hot liquid

• A hot gas

• A cold gas

Tags

NGSS.HS-PS3-2

A reaction that releases energy is

• Exothermic

• Endothermic

• Could be either

Tags

NGSS.HS-PS1-4