Q: Answer the following question given this paragraph: Many teens have emotional ups and downs. This is at least partly due to their changing hormone levels. Q: Changing levels of what substances partly explain emotional ups and downs in teens? A: | OPTIONS:
- nutrients
- acids
- enzymes
- hormones
A: hormones

Q: Answer the following question given this paragraph: An esterification is a condensation reaction in which an ester is formed from an alcohol and a carboxylic acid. Esterification is a subcategory of condensation reactions because a water molecule is produced in the reaction. The reaction is catalyzed by a strong acid, usually sulfuric acid. When the carboxylic acid butanoic acid is heated with an excess of methanol and a few drops of sulfuric acid, the ester methyl butanoate is produced. Methyl butanoate has the scent of pineapples. The reaction is shown below with both molecular and structural formulas. Q: What do you call a condensation reaction in which an ester is formed from an alcohol and a carboxylic acid? A: | OPTIONS:
- transesterification
- esterisation
- decarboxylation
- esterification
A: esterification

Q: Answer the following question given this paragraph: Ice is an example of solid matter. A solid is matter that has a fixed volume and a fixed shape. Figure below shows examples of matter that are usually solids under Earth conditions. In the figure, salt and cellulose are examples of crystalline solids. The particles of crystalline solids are arranged in a regular repeating pattern. The steaks and candle wax are examples of amorphous ("shapeless") solids. Their particles have no definite pattern. Q: What is the name for a matter that has a fixed volume and a fixed shape? A: | OPTIONS:
- gas
- stable
- liquid
- solid
A: solid

Q: Answer the following question given this paragraph: The nonmetals are elements located in the upper right portion of the periodic table. Their properties and behavior are quite different from those of metals on the left side. Under normal conditions, more than half of the nonmetals are gases, one is a liquid, and the rest include some of the softest and hardest of solids. The nonmetals exhibit a rich variety of chemical behaviors. They include the most reactive and least reactive of elements, and they form many different ionic and covalent compounds. This section presents an overview of the properties and chemical behaviors of the nonmetals, as well as the chemistry of specific elements. Many of these nonmetals are important in biological systems. In many cases, trends in electronegativity enable us to predict the type of bonding and the physical states in compounds involving the nonmetals. We know that electronegativity decreases as we move down a given group and increases as we move from left to right across a period. The nonmetals have higher electronegativities than do metals, and compounds formed between metals and nonmetals are generally ionic in nature because of the large differences in electronegativity between them. The metals form cations, the nonmetals form anions, and the resulting compounds are solids under normal conditions. On the other hand, compounds formed between two or more nonmetals have small differences in electronegativity between the atoms, and covalent bondingsharing of electronsresults. These substances tend to be molecular in nature and are gases, liquids, or volatile solids at room temperature and pressure. In normal chemical processes, nonmetals do not form monatomic positive ions (cations) because their ionization energies are too high. All monatomic nonmetal ions are anions; examples include the chloride ion, Cl, the nitride ion, N3, and the selenide ion, Se2. The common oxidation states that the nonmetals exhibit in their ionic and covalent compounds are shown in Figure 18.19. Remember that an element exhibits a positive... Q: When we move down a group of elements on the periodic table, what happens to their electronegativity? A: | OPTIONS:
- it increases
- it stays the same
- it doubles
- it decreases
A: it decreases