biology homework due tomorrow people............................................ Section 1 Chapter 2: Chemistry of Life 1. Which of the following statements is true? A. Mass is the scientific measurement of weight. B. Matter is anything that occupies space and has mass. C. A given object has the same weight on Earth as it has in space. D. More than 90 percent of the mass of living things is made of oxygen, carbon, hydrogen, and calcium. 2. Which of the following best describes the difference between an atom and an element? A. An element is made of one or more different types of atoms; an atom is the simplest particle of matter. B. An atom is the smallest piece of matter that cannot be broken down chemically into simpler kinds of matter. An element is a pure substance made of one type of atom. C. An element is the simplest particle of an atom that retains the properties of that atom. An atom is a pure substance that cannot be broken down chemically into simpler kinds of matter. D. An element is a pure substance of matter; each atom is made of one or more elements. These atoms form the building blocks of compounds and molecules. 3. Which of the following correctly describes an atom? A. An atom consists of a central core made of positive protons and neutral neutrons. Moving around the core at high speeds are tiny, negatively charged electrons. B. An atom consists of a nucleus made of positive electrons and neutral neutrons. Moving around the nucleus at high speeds are tiny, negatively charged protons. C. An atom consists of a nucleus made of positively charged neutrons and electrons. Moving around the nucleus at high speeds are tiny, negatively charged protons. D. An atom consists of two parts: a positively charged nucleus at the center of the atom and negatively charged protons,neutrons, and electrons balancing the charge as they move around the nucleus. 4. Which of the following statements is true? A. All atoms have the same number of protons. B. All atoms have the same number of neutrons. C. Different types of atoms have different numbers of protons. D. Ionic atoms of a given element have a different number of protons. 5. Which of the following best describes the difference between a compound and a molecule? A. A molecule consists of two or more compounds; a compound consists of two or more atoms. B. A compound consists of two or more molecules; a molecule consists of two or more atoms. C. A compound is the simplest part of a substance that retains all the properties of that substance, and it exists in a free state. A molecule is a pure substance made of two or more elements. D. A molecule is the simplest part of a substance that retains all the properties of that substance, and it exists in a free state . A compound is a pure substance made of two or more elements. 6. Which of the following is the simplest example of a molecule? A. H B. H2 C. H2O D. C6H12O6 7. The stability of an atom is determined by the A. age of the atom. B. size of the atom. C. number of protons in an atom. D. number of electrons in the outer energy level. 8. What is the difference between ionic bonds and covalent bonds? A. In ionic bonding, an atom loses an electron to form a stable bond. In covalent bonding, an atom gains an electron to form a stable bond. B. In ionic bonding, an atom gains an electron to form a stable bond. In covalent bonding, an atom loses an electron to form a stable bond. C. In ionic bonding, an ion with a positive charge is attracted to an ion with a negative charge. In covalent bonding, atoms share electron pairs to fill their outer electron levels. D. covalent bonding, an atom with a positive charge is attracted to an atom with a negative charge. In ionic bonding, two atoms share one or more pairs of electrons to gain stability. Section 2 Chapter 2: Chemistry of Life 1. Free energy, in a biological sense, is energy that A. forms spontaneously. B. does not cost the body anything to produce. C. is released during a chemical reaction. D. is available for work within a system. 2. When water freezes, the process A. requires additional energy. B. gives off thermal energy. C. occurs without energy, as it is not a biological process. D. requires an enzyme called frigidase. 3. In the chemical reaction CO2 + H2O =H2CO3, what is(are) the reactant(s)? A. CO2, H2O, and H2CO3 B. H2CO3 C. CO2 and H2O D. CO2 4. Which of the following statements does not describe an event that occurs during a chemical reaction? A. Chemical bonds are broken. B. New elements are made. C. Some elements are rearranged. D. New compounds are formed 5. Which of the following statements about the energy used in chemical reactions is false? A. In most cases, energy must be added to the reactants to start a reaction. B. Some reactions release energy as the reactants form new products. C. Some reactions use energy, or absorb energy, as the reactants form new products. D. Cells get most of the energy needed for metabolism from water. 6. In living organisms, enzymes play an important role in chemical reactions by A. allowing the reaction to proceed with little or no activation energy. B. serving as a source of activation energy for a reaction. C. becoming one of the key reactants. D. becoming one of the key products. 7. Which of the following best describes a redox reaction? A. A redox reaction is a dialysis reaction that occurs again and again in a loop. Some of the products become part of the reactants, which keeps the reaction going. B. A redox reaction is a combined reduction-oxidation reaction. In reduction, a reactant loses an electron. This electron is added to the other reactant in an oxidation reaction. C. A redox reaction is a combined reduction-oxidation reaction. In oxidation, a reactant loses an electron.This electron is added to the other reactant in a reduction reaction. D. Redox is short for reduction. During a reduction reaction, a reactant loses an electron to become appositively charged ion. section 2 Chapter 3: Chemistry of Life 1. Which of the following describes a solution? A. a mixture of one or more substances spread throughout another substance, such as blood B. a substance that dissolves in another substance, such as salt C. a substance in which another substance is dissolved, such as water D. any substance that is a liquid at normal Earth temperatures 2. Which of the following statements about the concentration of a solution is true? A. The more solvent that is used, the greater the concentration of the solution is. B. The most highly concentrated solutions are called aqueous solutions. C. Concentration is measured as the amount of solvent that is used to dissolve a fixed amount of solute. D. A saturated solution is so concentrated that it cannot dissolve any more solute. 3. The dissociation of water is the A. breaking apart of water molecules into the ions H+ and OH-. B. relative amount of acid or base within an aqueous solution. C. amount of solute that can be dissolved in water. D. amount of solute that can be dissolved in a fixed amount of water. 4. Which of the following is a hydroxide ion? A. H+ B. OH- C. H3O+ D. HCl 5. Which of the following statements describe a property of acids? A. Acids have a bitter taste. B. Acids have a sour taste. C. Acids feel slippery. D. Acids are an important part of soaps. 6. Which of the following substances is the most alkaline? A. intestinal fluid B. ammonia C. stomach fluid D. urine 7. On the pH scale, a 10 mL solution with a pH value of 4 has ____________ as many ____________ ions as a 10 mL solution with a pH of 5 does. A. twice, hydrogen B. twice, hydroxide C. 10 times, hydroxide D. 10 times, hydrogen 8. A buffer A. neutralizes small amounts of acid or base. B. turns acids into bases. C. turns bases into acids. D. makes acids more acidic and bases more alkaline.
Posted on: Tue, 23 Sep 2014 23:10:27 +0000
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