Regents Chemistry Test Preparation Practice Entropy

Which equation represents a change that results in an increase in disorder?*

(1) I₂(s) → I₂(g)

(2) CO₂(g) → CO₂(s)

(3) 2Na(s) + Cl₂(g) → 2NaCl(s)

(4) 2H₂(g) + O₂(g) → 2H₂O(ℓ)

Which term is defined as a measure of the randomness of a system?*

(1) heat

(2) entropy

(3) pressure

(4) temperature

The arrangement of particles is most ordered in a sample of*

(1) NaCl(aq)

(2) NaCl(ℓ)

(3) NaCl(g)

(4) NaCl(s)

During which phase change does the entropy of a sample of H₂O increase?*

(1) H₂O(g) → H₂O(ℓ)

(2) H₂O(g) → H₂O(s)

(3) H₂O(ℓ) → H₂O(g)

(4) H₂O(ℓ) → H₂O(s)

Given the balanced equation representing a reaction:

2H₂O(ℓ) + 571.6 kJ → 2H₂(g) + O₂(g)

What occurred as a result of this reaction?*

(1) Energy was absorbed, and entropy increased.

(2) Energy was absorbed, and entropy decreased.

(3) Energy was released, and entropy increased.

(4) Energy was released, and entropy decreased.

Which term is defined as a measure of the disorder of a system?*

(1) heat

(2) entropy

(3) kinetic energy

(4) activation energy

Entropy is a measure of the*

(1) acidity of a sample

(2) disorder of a system

(3) concentration of a solution

(4) chemical activity of an element

The amount of randomness of the atoms in a system is an indication of the*

(1) entropy of the system

(2) polarity of the system

(3) excited state of the atoms

(4) ground state of the atoms

Which phase change results in an increase in entropy?*

(1) I₂(g) → I₂(s)

(2) CH₄(g) → CH₄(ℓ)

(3) Br₂(ℓ) → Br₂(g)

(4) H₂O(ℓ) → H₂O(s)

Which term represents the disorder of a system?*

(1) entropy

(2) mole

(3) quanta

(4) pressure

When ice, H₂O(s), melts at 0°C, entropy increases because the*

(1) average kinetic energy of the particles increases

(2) average kinetic energy of the particles decreases

(3) particle arrangement is more random

(4) particle arrangement is less random

Base your answers to questions 12 on the information below and on your knowledge of chemistry.

The compounds KNO₃ and NaNO₃ are soluble in water.

Compare the entropy of 30. grams of solid KNO₃ at 20.°C with the entropy of 30. grams of KNO₃ dissolved in 100. grams of water at 20.°C.*

Base your answers to questions 13 on the information below and on your knowledge of chemistry.

The balanced equation below represents the reaction of glucose, C₆H₁₂O₆, with oxygen at 298 K and 101.3 kPa.

C₆H₁₂O₆(s) + 6O₂(g) → 6CO₂(g) + 6H₂O(ℓ)

Compare the entropy of the reactants to the entropy of the products.*

Base your answers to questions 14 on the information below and on your knowledge of chemistry.

Hydrazine, N₂H₄, is a compound that is very soluble in water and has a boiling point of 113°C at standard pressure. Unlike water, hydrazine is very reactive and is sometimes used as a fuel for small rockets. One hydrazine reaction producing gaseous products is represented by the balanced equation below.

N₂H₄(ℓ) → N₂(g) + 2H₂(g) + heat

Compare the entropy of the products to the entropy of the reactant for this reaction.*

Base your answers to questions 15 on the information below and on your knowledge of chemistry.

A few pieces of dry ice, CO₂(s), at −78°C are placed in a flask that contains air at 21°C. The flask is sealed by placing an uninflated balloon over the mouth of the flask. As the balloon inflates, the dry ice disappears and no liquid is observed in the flask.

Compare the entropy of the CO₂ molecules in the dry ice to the entropy of the CO₂ molecules in the inflated balloon.*