Entropy and Enthalpy

 

What is the symbol for entropy?

• a. H

• b. G

• c. S

• d. E

Entropy is a measure of

• a. accuracy

• b. the disorder of a system

• c. the attraction of a nucleus for an electron

• d. precision

Which of these processes represents a decrease in entropy?

• a. sublimation of CO₂

• b. boiling water

• c. condensation of steam on cold glass

• d. NaCl dissolving in water

Which of these reactions shows a DECREASE in entropy?

• a. CaCO₃(s) → CaO(s) + CO₂(g)

• b. 3O₂(g) → 2O₃(g)

• c. 2NH₃(g) → 3H₂(g) + N₂(g)

• d. C₆H₆(l) → C₆H₆(g)

The entropy will usually increase when

• a. a molecule is broken into two or more smaller molecules

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

• c. a solid changes to a liquid

• d. all of these

Which reaction has a +ΔS ?

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

• b. H₂O(g) + CO₂(g) → H₂CO₃(aq)

• c. C₂H₂O₂(g) → 2CO(g) + H₂(g)

• d.H₂(g) + I₂(g) → 2Hl(g)

Systems in nature tend to undergo changes toward

• a. lower energy and less disorder

• b. lower energy and more disorder

• c. higher energy and less disorder

• d. higher energy and more disorder

 

Which sample has the lowest entropy?

• a. mole of KNO₃(l)

• b. 1 mole of KNO₃(s)

• c. 1 mole of H₂O(l)

• d. 1 mole of H₂O(g)

 

Entropy increases from solid, liquid to gas. Why?

• a. Molecular disorder increases

• b. Molecules increase in number from solid to gas

• c. Molecules are heavier in solid

• d. Molecules are more reactive

Tags

NGSS.HS-PS3-4

Which sample has the lowest entropy?

• a. solid

• b. liquid

• c. aqueous

• d. gas