Q: Exemplified by rusty iron, what process is defined as the disintegration of a material due to chemical reactions with other substances in the environment? Read this paragraph and choose the correct option from the provided answers: Most of us are familiar with rusty iron: metal that has a dark red-brown scale that falls off an object, ultimately weakening it. Although we usually attribute rusting exclusively to iron, this process occurs with many materials. The more formal term for rusting is corrosion. Corrosion is defined as the disintegration of a material due to chemical reactions with other substances in the environment. In many cases, oxygen in the air causes the disintegration. Corrosion is not uniformly destructive. Although the corrosion of iron is generally considered bad, the corrosion of aluminum and copper forms a protective barrier on the surface of the metal, protecting it from further reaction with the environment. Having said that, it has been estimated that as much as 5% of expenditures in the United States apply to fixing problems caused by corrosion. The replacement of structures built with iron, steel, aluminum, and concrete must be performed regularly to keep these structures safe. As an example of what might happen, consider the story of the Silver Bridge on US Interstate 35, connecting West Virginia and Ohio. On December 15, 1967, the 39-year-old bridge collapsed, killing 46 people. The ultimate cause of the collapse was determined to be corrosion of a suspension chain on the Ohio side of the bridge. Corrosion is an example of the type of chemical reaction discussed in this chapter. Although we usually think of corrosion as bad, the reaction it typifies can actually be put to good use. One important type of chemical reaction is the oxidation-reduction reaction, also known as the redox reaction. Although we introduced redox reactions in - ball-ch04, - ball-ch04_s06, it is worth reviewing some basic concepts. Choices: - Metal Breakdown - magnesium - extraction - corrosion A:
corrosion

Q: How do leaves export sugar to roots and other nonphotosynthetic parts of the plant? Read this paragraph and choose the correct option from the provided answers: Choices: - stems - chloroplasts - glands - veins A:
veins

Q: Q: What can be classified as monoprotic or polyprotic based on the number of acidic hydrogens they contain? Read this paragraph and choose the correct option from the provided answers: Acids can be classified as monoprotic or polyprotic based on the number of acidic hydrogens they contain. Choices: - ions - cations - salts - acids A:
A: acids

Question: Q: The energy that enters the chloroplasts as sunlight becomes stored as what type of energy in organic compounds? Read this paragraph and choose the correct option from the provided answers: Choices: - radiation energy - thermal energy - defect energy - chemical energy A:
Answer: chemical energy

*Question*
Q: Interstitial carbides are produced by the reaction of most transition metals at high temperatures with what element? Read this paragraph and choose the correct option from the provided answers: temperatures with electropositive metals such as those of groups 1 and 2 and aluminum produces ionic carbides, which contain discrete metal cations and carbon anions. The identity of the anions depends on the size of the second element. For example, smaller elements such as beryllium and aluminum give methides such as Be2C and Al4C3, which formally contain the C4 ion derived from methane (CH4) by losing all four H atoms as protons. In contrast, larger metals such as sodium and calcium give carbides with stoichiometries of Na2C2 and CaC2. Because these carbides contain the C4 ion, which is derived from acetylene (HCCH) by losing both H atoms as protons, they are more properly called acetylides. As discussed in Chapter 21 "Periodic Trends and the ", Section 21.4 "The Alkaline Earth Metals (Group 2)", reacting ionic carbides with dilute aqueous acid results in protonation of the anions to give the parent hydrocarbons: CH4 or C2H2. For many years, miners' lamps used the reaction of calcium carbide with water to produce a steady supply of acetylene, which was ignited to provide a portable lantern. The reaction of carbon with most transition metals at high temperatures produces interstitial carbides. Due to the less electropositive nature of the transition metals, these carbides contain covalent metal carbon interactions, which result in different properties: most interstitial carbides are good conductors of electricity, have high melting points, and are among the hardest substances known. Interstitial carbides exhibit a variety of nominal compositions, and they are often nonstoichiometric compounds whose carbon content can vary over a wide range. Among the most important are tungsten carbide (WC), which is used industrially in high-speed cutting tools, and cementite (Fe3C), which is a major component of steel. Elements with an electronegativity similar to that of carbon form covalent carbides, such as silicon carbide (SiC; Equation 22.15) and boron carbide (B4C). These substances are extremely hard, have high... Choices: - hydrogen - oxygen - nitrogen - carbon A:
**Answer**
carbon

(Question)
Q: Land plants are classified into two major groups according to the absence or presence of what tissue? Read this paragraph and choose the correct option from the provided answers: The Major Divisions of Land Plants Land plants are classified into two major groups according to the absence or presence of vascular tissue, as detailed in Figure 14.8. Plants that lack vascular tissue formed of specialized cells for the transport of water and nutrients are referred to as nonvascular plants. The bryophytes, liverworts, mosses, and hornworts are seedless and nonvascular, and likely appeared early in land plant evolution. Vascular plants developed a network of cells that conduct water and solutes through the plant body. The first vascular plants appeared in the late Ordovician (461444 million years ago) and were probably similar to lycophytes, which include club mosses (not to be confused with the mosses) and the pterophytes (ferns, horsetails, and whisk ferns). Lycophytes and pterophytes are referred to as seedless vascular plants. They do not produce seeds, which are embryos with their stored food reserves protected by a hard casing. The seed plants form the largest group of all existing plants and, hence, dominate the landscape. Seed plants include gymnosperms, most notably conifers, which produce "naked. Choices: - disease - root - bacterial - vascular A:
(Answer)
vascular