1.
In an ethyne molecule, what is the hybridization of each of the carbons?
Correct Answer
D. Sp
Explanation
The correct answer is Sp. In an ethyne molecule, each carbon atom is bonded to two other atoms, resulting in a linear molecular geometry. The carbon atoms in ethyne are sp hybridized, meaning that they have one s orbital and one p orbital that have been combined to form two sp hybrid orbitals. These sp orbitals are used to form sigma bonds with the other atoms in the molecule. Therefore, the hybridization of each carbon in ethyne is Sp.
2.
What is the approximate heat of vaporization of water at its boiling point?
Correct Answer
C. 333.7 Kj
Explanation
The approximate heat of vaporization of water at its boiling point is 333.7 Kj. This is the amount of heat energy required to convert one mole of liquid water into vapor at its boiling point, without changing its temperature.
3.
Which element was the first ever artificially created?
Correct Answer
B. Technetium
Explanation
Technetium was the first ever artificially created element. It was discovered in 1937 by Italian physicist Emilio Segrè and his team. They bombarded molybdenum with deuterons in a cyclotron, creating technetium-97. This marked the first successful synthesis of an element that does not occur naturally on Earth. Technetium is a silvery-gray metal and is commonly used in medical imaging, particularly in nuclear medicine scans. Its discovery was significant as it demonstrated that elements could be created through artificial means, expanding our understanding of the periodic table.
4.
What is the molecular geometry of the molecule sulfur hexafluoride?
Correct Answer
D. Octahedral
Explanation
The correct answer is Octahedral. This is because sulfur hexafluoride (SF6) has six fluorine atoms bonded to a central sulfur atom. The molecule has a total of six electron pairs around the sulfur atom, resulting in an octahedral geometry. In an octahedral arrangement, the six electron pairs are spread out as far as possible, creating a symmetrical shape with bond angles of 90 degrees.
5.
Which is more abundant in the earth's crust?
Correct Answer
C. Uranium
Explanation
Uranium is more abundant in the earth's crust compared to the other elements listed. Uranium is a naturally occurring element and is relatively common in the earth's crust, with an average abundance of about 2.8 parts per million. On the other hand, gold, silver, and mercury are much less abundant in the earth's crust. Gold and silver are considered precious metals and are found in much lower concentrations, while mercury is a relatively rare element in the earth's crust. Therefore, uranium is the most abundant element among the options provided.
6.
What solution contains the same ratio of chemical constituents after it is distilled?
Correct Answer
A. Azeotropic Mixture
Explanation
An azeotropic mixture is a solution that contains the same ratio of chemical constituents after it is distilled. This means that even after distillation, the composition of the solution remains constant. In other words, the components of the solution have a specific ratio that cannot be altered by distillation. Therefore, an azeotropic mixture is the correct answer to the question.
7.
Who demonstrated that the rate of diffusion of a gas is inversely proportional to the square root of its density?
Correct Answer
A. Graham
Explanation
Graham demonstrated that the rate of diffusion of a gas is inversely proportional to the square root of its density.
8.
Which will have the smallest increase in temperature for the same amount of heat?
Correct Answer
D. Water
Explanation
Water will have the smallest increase in temperature for the same amount of heat because it has a high specific heat capacity. This means that it requires a large amount of heat energy to raise its temperature compared to the other substances listed. Copper, iron, and glass have lower specific heat capacities, so they will experience a greater increase in temperature for the same amount of heat.
9.
When a CFC molecule is struck by UV radiation, what kind of cleavage gives rise to the chlorine free radical?
Correct Answer
C. Homolytic Cleavage
Explanation
Homolytic cleavage is the process in which a covalent bond is broken evenly, with each atom receiving one of the shared electrons. When a CFC molecule is struck by UV radiation, the energy is absorbed by the molecule, causing the bond between the carbon and chlorine atoms to break. This results in the formation of a chlorine free radical, with each atom retaining one electron from the original bond. Therefore, homolytic cleavage is the type of cleavage that gives rise to the chlorine free radical in this scenario.
10.
What kind of cell has a negative EMF and a positive Gibbs free energy?
Correct Answer
B. Electrolytic Cell
Explanation
An electrolytic cell is the correct answer because it is the only type of cell that can have a negative EMF and a positive Gibbs free energy. In an electrolytic cell, electrical energy is used to drive a non-spontaneous chemical reaction, which results in a negative EMF. The positive Gibbs free energy indicates that the reaction is non-spontaneous and requires an input of energy. Galvanic cells, on the other hand, have a positive EMF and a negative Gibbs free energy, indicating that they are spontaneous and release energy. The Danielle cell is a type of galvanic cell, so it cannot have a negative EMF and a positive Gibbs free energy.
11.
Which two transition metals do not exhibit diamagnetism?
Correct Answer
A. Zn And Sc
Explanation
Zinc (Zn) and Scandium (Sc) are the two transition metals that do not exhibit diamagnetism. Diamagnetic substances have all of their electrons paired up in their atomic or molecular orbitals, resulting in no net magnetic moment. Both Zn and Sc have completely filled d orbitals, which means all of their electrons are paired up and there is no unpaired electron to generate a magnetic field. Therefore, they do not show any magnetic properties and are considered diamagnetic.
12.
What was the fifth unearthly element from the days of Aristotle?
Correct Answer
D. Quintessence
Explanation
Quintessence was considered the fifth unearthly element from the days of Aristotle. In ancient Greek philosophy, it was believed to be a substance that made up the celestial bodies and existed beyond the four earthly elements of earth, air, fire, and water. Quintessence was thought to be pure and incorruptible, representing the divine and eternal. This concept of quintessence was influential in early scientific and philosophical discussions about the nature of the universe.
13.
What is the name of the temperature at which Helium I becomes Helium II?
Correct Answer
A. Lambda Point
Explanation
The name of the temperature at which Helium I becomes Helium II is the Lambda Point.
14.
Which element was named after the Greek mortal woman who claimed her 12 children were better than the goddess Leto's two children?
Correct Answer
B. Niobium
Explanation
Niobium was named after the Greek mortal woman, Niobe, who boasted that her 12 children were superior to the two children of the goddess Leto. As a result, Leto's children, Apollo and Artemis, were sent to punish Niobe, causing the death of all her children. The element Niobium was named in reference to this Greek mythological story.
15.
Which of the following ionic solids would you expect to have the highest lattice energy?
Correct Answer
C. Mgo
Explanation
MgO would be expected to have the highest lattice energy because it consists of a smaller cation (Mg2+) and a smaller anion (O2-) compared to the other options. The smaller the ions, the stronger the electrostatic attraction between them, resulting in a higher lattice energy.