Question 1

Aluminum is an active metal, but does not corrode as iron does because

Accepted Answer

Aluminum reacts with oxygen in the air to form a thin layer of aluminum oxide on its surface, which serves as a protective layer against further corrosion. This is why aluminum does not corrode as iron does, even though aluminum is an active metal. Aluminum reacts with oxygen in the air to form a thin layer of aluminum oxide on its surface. This layer acts as a protective barrier against further corrosion.

Question 2

Which is a covalent oxide?

Accepted Answer

BeO (Beryllium Oxide) is a covalent oxide because beryllium has a relatively small size and high ionization energy, which makes it form covalent bonds rather than ionic bonds.

Question 3

The final step of the purification of copper involves electrorefining in which copper is separated from nickel and iron by being reduced at the cathode of a cell. Why are nickel and iron not reduced?

Accepted Answer

Nickel and iron have more negative reduction potentials than copper, which means they require more energy to be reduced at the cathode. Therefore, copper is reduced first before nickel and iron. The reduction potentials of nickel and iron are more negative than copper's, which means that copper has a higher tendency to be reduced than nickel and iron. Therefore, when an electric current is passed through the cell in electrorefining, copper is reduced at the cathode while nickel and iron remain in solution as ions.

Question 4

The Hall process refers to

Accepted Answer

The Hall process specifically refers to the industrial process of electrolysis used to produce aluminum metal from bauxite ore.

Question 5

Which is an example of a basic oxide?

Accepted Answer

Basic oxides are oxides that react with acidic solutions to form a salt and water. BaO is a basic oxide as it reacts with acidic solutions to form salts such as BaSO4 and water. The other options are either not oxides or not basic oxides.

Question 6

Magnesium reacts with dilute hydrochloric acid according to which of these equations?

Accepted Answer

Magnesium reacts with dilute hydrochloric acid to produce hydrogen gas and magnesium chloride. The correct equation is: Mg + 2HCl → H2 + MgCl2

Question 7

Which statement is not correct?

Accepted Answer

Metallic aluminum is not toxic to humans. In fact, aluminum is commonly used in various products such as cookware and packaging. However, excessive consumption or exposure to certain forms of aluminum (such as aluminum salts in antiperspirants or occupational exposure to fine aluminum powders) has been linked to health concerns.

Question 8

_____ consists of potassium nitrate, wood charcoal, and sulfur.

Accepted Answer

Gunpowder consists of potassium nitrate, wood charcoal, and sulfur. A is incorrect as salt peter and Chile salt peter are the same thing. C is incorrect as carborundum has nothing to do with gunpowder. E is incorrect as anglesite is a mineral composed of lead sulfate.

Question 9

The mineral cryolite, Na₃AlF₆, is used in the Hall process for aluminum production as

Accepted Answer

Cryolite is used as a solvent for alumina in the Hall process for aluminum production. It lowers the melting point of alumina, allowing for the electrolysis process to occur at a lower temperature and reducing energy costs. Cryolite also helps to increase the conductivity of the electrolyte. Cryolite is used as a solvent for the alumina in the Hall process, allowing for lower operating temperatures and reduced energy consumption. It is not the source of aluminum ore, a reducing agent, or a material that forms slag to remove impurities.

Question 10

What is the molecular shape of AlF₃?

Accepted Answer

AlF3 has a trigonal planar shape because aluminum forms three bonds with fluorine atoms, and there are no lone pairs on the aluminum atom, resulting in a planar structure with 120-degree bond angles.

Question 11

Which reaction is a good small-scale laboratory method for the preparation of hydrogen?

Accepted Answer

Choice C shows a reaction between sodium hydride and water, which is a common small-scale laboratory method for the preparation of hydrogen gas. Sodium hydride reacts with water to produce hydrogen gas and sodium hydroxide. The other choices show reactions that do not directly produce hydrogen gas or are not practical for small-scale laboratory preparation of hydrogen.

Question 12

In gunpowder, which component is present in the highest percent by mass?

Accepted Answer

Potassium nitrate (also known as saltpeter) is the main ingredient in gunpowder, typically making up around 75% of the mixture by weight. Wood charcoal and sulfur make up the remaining 25%. Chile salt peter is not a component of gunpowder. Ammonia is not used in the production of gunpowder.

Question 13

Which undergoes electrolysis to form calcium metal?

Accepted Answer

Calcium chloride (CaCl2) undergoes electrolysis to form calcium metal along with chlorine gas at the anode. This is because it is a salt that dissociates into ions in molten form, allowing the electrolytic process to occur.

Question 14

Which statement is not correct?

Accepted Answer

This statement is not correct because aluminum hydroxide is amphoteric, meaning it can act as both an acid and a base. Therefore, it is incorrect to say that aluminum hydroxide can ONLY act as a base.

Question 15

The Hall process involves the reduction of Al₂O₃ to aluminum by

Accepted Answer

The Hall process involves the electrolysis of Al₂O₃ to produce aluminum. The other options (A, B, C, and D) are not involved in the Hall process. The Hall process involves the use of electrolysis to reduce Al₂O₃ to aluminum.

Question 16

The process used to produce metals with a purity of more than 99.99% is called

Accepted Answer

Zone refining is a technique used to produce highly pure metals by moving a molten zone along a solid metal, which allows impurities to be segregated and removed.

Question 17

The Downs cell is used in the production of

Accepted Answer

The Downs cell is used in the production of sodium through the electrolysis of molten sodium chloride. The Downs cell is primarily used in the production of sodium through the electrolysis of molten sodium chloride (NaCl).

Question 18

In the production of aluminum, bauxite is heated with sodium hydroxide solution to ________.

Accepted Answer

The heating with sodium hydroxide solution is known as the Bayer process, which is used to extract alumina from bauxite. During this process, sodium hydroxide solution is added to bauxite, which reacts with the silica present in it to form sodium aluminum silicate and water. This compound is soluble in the solution and can be separated from the mixture. Thus, heating with sodium hydroxide removes silica from bauxite.

Question 19

Which of these ions is most likely to substitute for Ca²⁺ in the human body?

Accepted Answer

Strontium (Sr) is a chemical element that belongs to the same group as calcium in the periodic table. It has similar chemical properties to calcium and can substitute for it in certain biological processes. Therefore, Sr²⁺ is the most likely ion to substitute for Ca²⁺ in the human body. Strontium (Sr) is a chemically similar ion to calcium (Ca) and thus can substitute for Ca in certain biochemical processes in the body. The other ions listed have different chemical properties and are less likely to substitute for Ca in the body.

Question 20

Which metal's commercial source is seawater?

Accepted Answer

Magnesium is primarily obtained from seawater through the process of electrolysis. The other options are not obtained from seawater as their commercial sources.

Quiz 24: Nonmetallic Elements and Their Compounds

Aluminum is an active metal, but does not corrode as iron does because

Which is a covalent oxide?

The final step of the purification of copper involves electrorefining in which copper is separated from nickel and iron by being reduced at the cathode of a cell. Why are nickel and iron not reduced?

The Hall process refers to

Which is an example of a basic oxide?

Magnesium reacts with dilute hydrochloric acid according to which of these equations?

Which statement is not correct?

_____ consists of potassium nitrate, wood charcoal, and sulfur.

The mineral cryolite, Na3AlF6, is used in the Hall process for aluminum production as

What is the molecular shape of AlF3?

Which reaction is a good small-scale laboratory method for the preparation of hydrogen?

In gunpowder, which component is present in the highest percent by mass?

Which undergoes electrolysis to form calcium metal?

Which statement is not correct?

The Hall process involves the reduction of Al2O3 to aluminum by

The process used to produce metals with a purity of more than 99.99% is called

The Downs cell is used in the production of

In the production of aluminum, bauxite is heated with sodium hydroxide solution to ________.

Which of these ions is most likely to substitute for Ca2+ in the human body?

Which metal's commercial source is seawater?

The mineral cryolite, Na₃AlF₆, is used in the Hall process for aluminum production as

What is the molecular shape of AlF₃?

The Hall process involves the reduction of Al₂O₃ to aluminum by

Which of these ions is most likely to substitute for Ca²⁺ in the human body?