AnswersCR Chemistry S1 Q3050OXLab: Calorimetry and Specific Heat

Enthalpy, Entropy, and Free Energy Answers

15 verified answers4 views
1
Free Preview

Which process involves a decrease in entropy?

A
burning natural gas
B
water freezing into ice
C
water evaporating on heating
D
dry ice subliming
4

Which process is spontaneous?

A
electrolysis of water into oxygen and hydrogen
B
spreading of a strong fragrance of perfume in a room
C
separation of sodium and chlorine from sodium chloride
D
removal of iron fillings from a mixture by using a magnet
5

Which process involves an increase in entropy?

A
crystallization of a solute from a solution
B
ice melting into liquid water
C
iodine vapor forming solid iodine
D
condensing a gas into a liquid
6

Which statement describes spontaneous processes?

A
proceed without continuous external influence and have an overall negative free energy change
B
proceed without continuous external influence and have an overall positive free energy change
C
proceed with continuous external influence and have an overall negative free energy change
D
proceed with continuous external influence and have an overall positive free energy change
7

Which statement describes a system that consists of sugar crystals dissolving in water?

A
The system becomes more ordered and has an increase in entropy.
B
The system becomes more ordered and has a decrease in entropy.
C
The system becomes more disordered and has an increase in entropy.
D
The system becomes more disordered and has a decrease in entropy.
8

The reaction below proceeds spontaneously at 298 K. NH3(g) +Cl2(g)NH4Cl(s)What is the sign of the entropy change, S?

Question illustration
A
S is negative because the product is less random than the reactants.
Option A
B
S is negative because the reactants are less random than the product.
Option B
C
S is positive because the product is less random than the reactants.
Option C
D
S is positive because the reactants are less random than the product.
Option D
16

The equation CaCO3(s) CaO(s) + CO2(g) shows the decomposition of calcium carbonate. H = 178.3 kJ/mol, and S = 160.5 J/(molK). The free energy change for the reaction is 130.5 kJ/mol. Which correctly states the temperature at which the reaction took place and whether the reaction is spontaneous or nonspontaneous? Use G = H – TS.

Question illustration
A
0.30 K, spontaneous
B
1.92 K, spontaneous
C
297.8 K, nonspontaneous
D
1,924 K, nonspontaneous
17

What is Grxn for the equation below?NaOH(aq) + HCl(aq) H2O(l) + NaCl(aq)Hrxn = -56.13 kJSrxn = 87.1 J/KT = 303 KUse G = H – TS.

Question illustration
A
–82.5 kJ
B
–29.7 kJ
C
26,500 kJ
D
27,000 kJ
18

Marcela dissolves 80.0 g of ammonium nitrate in 50.0 mL of water at room temperature and notes that the temperature of the solution decreases by 5.0°C. Which correctly designates the signs of H, S, and G for this reaction?

Question illustration
A
H > 0, S > 0, and G < 0
Option A
B
H 0, and G < 0
Option B
C
H > 0, S > 0, and G > 0
Option C
D
H 0
Option D
19

Which process or processes produce an increase in entropy?i. N2(g) + 3H2(g) NH3(g)ii. C10H8(g) C10H8(s)iii. CH3OH(l) CH3OH(aq)

Question illustration
A
i only
B
ii and iii
C
iii only
D
i and iii
20

Consider the reaction 2SO2(g) + O2(g) 2SO3(g).SubstanceHf (kJ/mol)S (J/(molK))SO3(g)–396130.58SO2(g)–297191.50O2(g)0205.00What is the Grxn of this reaction, and would it be spontaneous or nonspontaneous at 300.0 K? Use G = H – TS.

Question illustration
A
–296 kJ/mol, spontaneous
B
–296 kJ/mol, nonspontaneous
C
–100 kJ/mol, spontaneous
D
–100 kJ/mol, nonspontaneous

Did you find these answers helpful?