Module 12
True or False:
All Chlorates are soluble in water.
True
Which type of reaction releases heat where enthalpy will be negative and is a bond forming reaction?
Exothermic Reaction
What is the equilibrium constant for the decomposition of ammonia at 25 °C, given that the ΔG°f of NH₃(g) = –16.5 kJ/mol?
Use ΔG°f(N₂) = 0 kJ/mol and ΔG°f(H₂) = 0 kJ/mol.
2NH3(g)⇌N2(g)+3H2(g)
K ≈ 1.65 × 10⁻⁶
Based on the balanced chemical equation below, does the reaction show an overall increase or decrease in entropy (ΔS°)?
2NO2(g)→N2O4(g)
A. Increase in entropy
B. Decrease in entropy
C. No change in entropy
D. Cannot be determined without temperature data
B. Decrease in entropy
Which ocean is the largest ocean?
Pacific Ocean
Lead (II) Sulfate will be (Soluble/Insoluble) due to this sulfate (Always/Sometimes/Never) being soluble.
Insoluble & Somtimes
Which of the following phase changes is associated with the greatest increase in entropy?
A) Ice melting into liquid water
B) Water vapor condensing into liquid
C) Liquid water freezing into ice
D) Liquid water evaporating into gas
D) Liquid water evaporating into gas
Consider an isothermal reaction (25 °C, P = 1 atm) involving the combustion of propane. Write down and balance the chemical equation for the complete combustion of propane (C₃H₈).
C3H8(g)+5O2(g)→3CO2(g)+4H2O(g)
Which of the following statements correctly describes the relationship between Gibbs Free Energy (ΔG\Delta GΔG), Enthalpy (ΔH\Delta HΔH), and Entropy (ΔS\Delta SΔS) at constant temperature?
A. A reaction is spontaneous if ΔH>0 and ΔS>0
B. A reaction is spontaneous if ΔH<0\ and ΔS<0
C. A reaction is spontaneous if ΔG<0, which can occur when ΔH is negative and ΔS is positive
D. A reaction is spontaneous if ΔG>0, which occurs when both ΔH and ΔS are positive
C. A reaction is spontaneous if ΔG<0, which can occur when ΔH is negative and ΔS is positive
Which planet shares its name with a chemical element?
Mercury
What is the Ksp expression for Manganese (II) sulfide?
MnS (s)⇌Mn^2+(aq)+S^2−(aq)
Ksp=[Mn^2+][S^2−]
Determine if the following reaction is spontaneous by finding the equilibrium constant at 25 oC if the ΔG° for PCl3 and PCl5 are -267.8 kJ/mol and -305.0 kJ/mol, respectively.
Cl2(g) + PCl3(g) ⇌ PCl5(g)
ΔG°rxn = –37.2 kJ/mol
K ≈ 3.2 × 10⁶ → The reaction is spontaneous (since K » 1 and ΔG° < 0).
A chemical reaction is found to be non-spontaneous in the forward direction under standard conditions. Which of the following statements is true regarding the reverse reaction?
A. The reverse reaction is also non-spontaneous, with ΔG° > 0 and K > 1
B. The reverse reaction is spontaneous, with ΔG° < 0 and K > 1
C. The reverse reaction is spontaneous, with ΔG° < 0 and K < 1
D. The reverse reaction is spontaneous, with ΔG° < 0 and K > 1
B. The reverse reaction is spontaneous, with ΔG° < 0 and K > 1
How would a flask (solution) feel temperature wise in an endothermic reaction?
Cold
What is the scientific name for the Northern Lights?
Aurora Borealis
Which saturated condition contains a high solute concentration than what can dissolve at equilibrium. In this state, heating the solution enough until it dissolves then slowly cooling it down will allow it to crystallize due to its instability.
Supersaturated Solution
Qsp > Ksp
True or False:
You will have a spontaneous reaction if your Entropy is Negative and Enthalpy is Positive
False
It will never be spontaneous
Calculate the enthalpy change (ΔH°) for the following reaction at standard state:
2C(s)+3H2(g)→C2H6(g)
Use the following standard enthalpies of formation (ΔH°f):
ΔH°f(C(s)) = -285 kJ/mol (carbon in its standard state)
ΔH°f(H₂(g)) = -1139 kJ/mol (hydrogen in its standard state)
ΔH°f(C₂H₆(g)) = –947.7 kJ/mol
What is the enthalpy change (ΔH°) for the reaction?
The enthalpy change (ΔH∘\Delta H^\circΔH∘) for the reaction is 3039.3 kJ/mol.
Determine which has higher entropy: One mole of solid arsenic (As) at room temperature or one mole of arsenic trioxide (As₂O₃) as a gas at room temperature.
Arsenic trioxide (As₂O₃) as a gas at room temperature has higher entropy.
What is the only bird that can fly backwards?
Hummingbird
Calculate the solubility (in mol/L) of barium fluoride (BaF₂) given that its Ksp=1.7×10^−6.
7.5×10−3mol/L
If K is greater than 1, it will be (Reactant/Product) favored, and G will be (Negative/Positive), meaning that the system will be (Spontaneous/Non-spontaneous)
Product
Negataive
Spontaneous
The solubility of calcium hydroxide (Ca(OH)₂) in water at 25°C is measured to be 1.85 × 10⁻³ mol/L. Calculate the solubility product constant (Ksp) for calcium hydroxide.
Ca(OH)2(s)⇌Ca2+(aq)+2OH−(aq)
A. 3.4×10−6
B. 2.53x10-8
C. 1.85×10−5
D. 1.37×10−5
Ksp=2.53×10−8
Discuss the sign of ΔH(system) = ΔH(reaction) for the following reaction:
Freezing of water, H₂O (l) ⇌ H₂O (s) at 0°C
ΔH(system) is negative for the freezing of water because it is an exothermic process where heat is released as water freezes into ice.
What is the Capital City of Canada
Ottawa