DAY 1 YARN Flashcards
(441 cards)
Which type of colloid is whipped cream?
A. sol
B. aerosol
C. foam
D. emulsion
C. foam
What is the orbital angular momentum quantum number of the electron that is most easily removed when ground-state chlorine is ionized?
A 3
B. 2
C. 1
D. 0
C. 1
What is the Balmer series limit?
A. 122 nm
B. 365 nm
C. 477 nm
D. 656 nm
B. 365 nm
The Balmer series limit corresponds to the shortest possible wavelength, which occurs when an electron transitions from infinity (n = ∞) to n = 2.
Which is the largest?
A. Sulfide
B. Chloride
C. Argon
D. Potassium ion
A. Sulfide
Sulfide (S²⁻): When sulfur gains two electrons to become a sulfide ion, its size increases significantly because of electron-electron repulsion in the outer shell.
Chloride (Cl⁻): When chlorine gains one electron to form a chloride ion, its size also increases, but not as much as the sulfide ion because it only gains one electron.
Argon (Ar): Argon is a neutral noble gas with a relatively small atomic radius because it has a full outer shell and no electron-electron repulsion.
Potassium ion (K⁺): When potassium loses one electron to become a 𝐾+ ion, its size shrinks significantly, as it loses its entire outer shell.
Which of the following is isoelectronic with azide ion?
A. NO2-
B. CO2
C. SO2
D. O3
B. CO2
Azide= N3^-
Each nitrogen atom contributes 7 electrons, so
3×7=21 electrons.
The negative charge (−1) adds 1 electron, so the total becomes 22 electrons.
CO2 = 6 +2(8) = 22 electrons
Atomic number = no of electrons (except for ions) = no of protons
What is the molecular geometry of bromine trifluoride?
A. trigonal planar
B. trigonal pyramidal
C. t-shaped
D. trigonal bipyramidal
C. t-shaped
What is the electron pair geometry of sulfur tetrafluoride?
A. tetrahedral
B.see-saw
C. square planar
D. trigonal bipyramidal
D. trigonal bipyramidal
What is the bond order of the C-O bond in the carbonate ion?
A. 1
B 1.33
C 1.5
D. 2
B 1.33
It is the sum of the average mass of atoms in an ionic compound.
A. atomic mass
B. molar mass
C. formula mass
D. molecular mass
C. formula mass
Which can be reacted to magnesium to form magnesium nitride.
A. ammonia
B. sodium nitrate
C. hydrazine
D. none of these
A. ammonia
Ammonia (NH₃) can react with magnesium to form magnesium nitride (Mg₃N₂). The reaction can be represented as:
3Mg +N2→Mg3N2
However, ammonia can provide nitrogen in the presence of magnesium under certain conditions.
It has been observed that there are more dead fish in a lake in summer compared to the colder season. Which of the following best explains the situation?
A. More food is dissolved in the lake during warmer season
B. More food is dissolved in the lake during colder season
C. Less oxygen is dissolved in the lake during warmer season
D. Less oxygen is dissolved in the lake during colder season
C. Less oxygen is dissolved in the lake during warmer season
The solubility of gases in liquids generally decreases with increasing temperature. As the temperature of water rises, the kinetic energy of water molecules increases, causing gas molecules (like oxygen) to escape more easily from the water.
In the equilibrium reaction above, the [Co(H2O)]2* exhibits pink color, while [CoCl1]2 exhibits blue color. Which of the following is true?
A. Upon heating, the purple solution turned blue, therefore the reaction is exothermic.
B. Upon heating, the purple solution turns blue, therefore the reaction is endothermic.
C. Upon cooling, the purple solution turns pink, therefore the reaction is exothermic.
D. Upon cooling, the purple solution turned blue, therefore the reaction is endothermic
B. Upon heating, the purple solution turns blue, therefore the reaction is endothermic.
When you heat the solution and it turns blue, this means that the reaction is shifting to produce more of the blue species ([CoCl₄]²⁻). According to Le Chatelier’s principle, if heating causes the reaction to shift to the right (producing more blue), it indicates that the forward reaction absorbs heat — meaning the reaction is endothermic.
Carbon-14 most likely decays into
A. C-12
B. N-14
C. C-13
D. N-15
B. N-14
Carbon-14 undergoes beta decay, where one of its neutrons is converted into a proton, emitting an electron (beta particle) in the process. As a result, the element changes from carbon to nitrogen.
- Uranium-235 is one of the most common fuels used in nuclear power plants. On the other hand, Uranium-238 cannot be used as a fuel in a nuclear power plant. Which of the following best explains why Uranium-238 cannot be used as a fuel?
A. Uranium-238 does not undergo radioactive decay.
B. Uranium-238 does not undergo fission easily enough to be used as a fuel.
C. There is not enough Uranium-238 in naturally occurring uranium to use it as a fuel.
D. Uranium-238 is not a naturally occurring isotope of uranium.
B. Uranium-238 does not undergo fission easily enough to be used as a fuel.
Uranium-235 readily undergoes fission when bombarded with thermal neutrons, releasing large amounts of energy. However, Uranium-238 does not undergo fission under the same conditions because it is much more stable and requires fast neutrons to fission, which are harder to control in nuclear reactors.
What is the oxidation state of chromium in dichromic acid?
A. +2
B. +3
C. +6
D. +12
C. +6
In the reaction: 6 Na2S2O3 + 3I2→3 Na2S406 +6 Nal, which of the following is the reducing agent?
A. I
B. S
C. I2
D. Na2S2O3
D. Na2S2O3
Which of the following material/s is/are used in rechargeable batteries?
A. zinc-carbon
B. silver oxide
C nickel-cadmium
D. none of the above
C nickel-cadmium
Which of the following effuses almost four times slower than hydrogen?
A. helium
B. chlorine
C. ethane
D. water vapor
C. ethane
A mole of which gas has the smallest volume at 0°C and 1 atm?
A. He
B. CO2
C. SO2
D. Xe
C. SO2
At 0°C and 1 atm, one mole of any ideal gas occupies about 22.4 liters. However, real gases can behave differently.
He (Helium): Ideal behavior, weak forces.
CO₂ (Carbon Dioxide): Heavier, but still close to ideal.
SO₂ (Sulfur Dioxide): Stronger forces, behaves less ideally.
Xe (Xenon): Heavy noble gas, behaves similarly to He.
SO₂ has the strongest intermolecular forces, so it will occupy a smaller volume than the others.
Given that dU = TdS - PdV and that H = U + PV, which of the following is TRUE?
A. dH = TdS + VdP
B. dH = S&T - VdP
C. dH = dU + PdV
D. dH = dU TdS
A. dH = TdS + VdP
At constant T and P, a system will be in equilibrium when which of the following quantities is at minimum?
A. W
B. H
C. A
D. G
D. G
At constant temperature and pressure, the Gibbs free energy (G) is a measure of the maximum reversible work that can be performed by a thermodynamic system.
Spontaneity: A reaction happens naturally if it lowers Gibbs free energy (G). If G is at a minimum, small changes will make it go up, meaning the system is stable.
Equilibrium Condition: At equilibrium, reactions go forward and backward at the same rate. This balance happens when G is at its lowest.
Thermodynamic Stability: When G is minimized, the system is stable and won’t change on its own unless something disrupts it.
The Helmholtz free energy is positive when changes in internal energy and entropy are both positive at
A. high temperatures
B. low temperatures
C. all temperatures
D. only at absolute zero temperature
B. low temperatures
Liquid water is injected into an oven at 400 K. What are the signs of AG, AH, and AS of the process?
A. +, + +
B. - - -
C. - + +
D. +, -, +
C. - + +
Which of the following is TRUE at extremely high temperatures?
A. The chemical potential of solid, liquid, and gas are all equal.
B. The chemical potential of the gas is the lowest.
C. Solid is the most stable phase
D. None of the above.
B. The chemical potential of the gas is the lowest.