Thermochemistry
The enthalpy of solution for solid ammonium nitrate (NH₄NO₃) is +25.7 kJ/mol. If a sample of NH₄NO₃ is dissolved in water in a beaker, will the beaker feel warm or cold to the touch after dissolution?
The beaker will feel cold to the touch.
What is the difference between nuclear fission and nuclear fusion?
Bonus for an extra 50 points: Which one releases more energy?
Nuclear fission is when a parent nuclide decays into a daughter nuclide.
Nuclear fusion is when 2+ nuclides fuse to form 1 nuclide.
Nuclear fusion generates more energy.
If n = 6 and l = 3, how many electrons are in the given orbital?
14 electrons
Rank the following in order of increasing wavelength:
X-rays, Radio Waves, Gamma Rays, Microwaves
Gamma Rays < X-rays < Microwaves < Radio Waves
What type of decay would ¹⁸₉F undergo?
Bonus question for an extra 50 points: Write out the decay equation.
Positron Emission
918F + e- →818O
Consider the following reaction:
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
Calculate the ΔH° for the above reaction using the following standard enthalpies of formation:
C₂H₅OH(l): -277.7 kJ/mol
CO₂(g): -393.5 kJ/mol
H₂O(l): -285.8 kJ/mol
ΔH° = -1366.7 kJ/mol
The isotope strontium-90 is radioactive and undergoes decay.
Determine the most likely type of decay
Write the balanced nuclear equation for this decay, showing the product isotope and all emitted particles.
Beta Decay
3890Sr→3990Y+e-
What characteristics of the orbital do each of the quantum numbers (n, l, ml, ms) represent?
n = shape
l = size
ml = orientation of orbital
ms = spin
Rank the following in order of increasing energy
a) n = 5 --> n = 2
b) n = 7 --> n = 3
c) n = 1 --> n = 4
d) n = 2 --> n = 5
n = 7 → 3 < n = 5 → 2 < n = 2 → 5 < n = 1 → 4
Write a formation reaction for Hg₂CrO₄(s) with states of matter included.
Hg₂(ℓ) + 1 Cr(s) + 2 O₂(g) → Hg₂CrO₄(s)
A 45.8 g copper block (c = 0.385 J/g·K) at 78.4°C is placed into an insulated calorimeter containing 102.6 g of water (c = 4.184 J/g·K) at 24.7°C. Assuming no heat is lost to the calorimeter or surroundings, determine the final temperature of the system when thermal equilibrium is reached.
Tf = 299.8 K or 26.8 °C
A radioactive sample initially contains 100% of a parent nuclide. After some time, measurements show that 21.9% of the original parent nuclide remains. How many half lives have passed?
2.19 half lives have passed
Arrange the following species in order of increasing radius: Ca²⁺, K⁺, S²⁻, Cl⁻, Ga³⁺.
Ga³⁺ < Ca²⁺ < K⁺ < Cl⁻ < S²⁻
In a Hydrogen atom, rank the following from lowest to highest energy
4s 3f 2d 4d
2d < 3f < 4s = 4d
Write the complete electron configuration of Au+
[1s22s22p63s23p64s23d104p65s24d105p64f145d10]
What is the ΔH for 2C(s) + H₂(g) → C₂H₂(g) given
C₂H₂(g) + ⁵⁄₂O₂(g) → 2CO₂(g) + H₂O(l) (ΔH = -1300 kJ)
C(s) + O₂(g) → CO₂(g) (ΔH = -394 kJ)
H₂(g) + ½O₂(g) → H₂O(l) (ΔH = -286 kJ)
+226 kJ
If 103290Lr underwent 2 alpha decays and 1 beta decay, what would the decay product be?
Bonus question for an extra 50 points: Would the decay product be stable?
²⁸²₁₀₀Fm
The decay product would not be stable.
Write the condensed electron configuration for Tungsten (W)
Bonus question for an extra 50 points: is W paramagnetic or diamagnetic?
[Xe]6s24f145d4
Remember the exceptions to the rule!!
W is paramagnetic
My bathmat has been smelling suspicious, so I turn the lights off and take a blacklight to examine it. To my horror, I see white glowing splotches all over the bathmat. What is the energy of the blacklight beam if the wavelength is 0.365 μm?
5.45×10-19 J
A radioactive nuclide undergoes a series of decays and eventually produces 82210Pb as a stable decay product. During the decay process, it emits 2 alpha (α) particles and 3 beta (β⁻) particles.
What was the original parent nuclide?
83218Bi (Bismuth-218)
A system consists of 8.32 g of a metal (specific heat = 0.00781 kJ/g·K) initially at 198.2°C. After a chemical process, the final temperature is 61.5°C. During the process, the surroundings do 575 J of work on the system.
What is Esys and Esurr?
Esys = -8307.7 J
Esurr = 8307.7 J
Calculate the binding energy of ³²S in kilojoules per mole (kJ/mol). ³²S has a mass of 31.972071 amu.
2.615×1010 kJ/mol
What are the quantum numbers for all of the Fe 3d electrons?
[3, 2, -2, +1/2]
[3, 2, -1, +1/2]
[3, 2, 0, +1/2]
[3, 2, 1, +1/2]
[3, 2, 2, +1/2]
[3, 2, -2, -1/2]
An electron in a hydrogen atom is excited between n=5 & n=2. What is the frequency of the transition?
6.91×1014 Hz
What is your TA's full name and major(s)?
Sarah Brown
Chemistry & Psychology