应用化学专业英语第二版课后练习题含答案Chapter OneMultiple Choice Questions1.The scientific method of problem solving consists of___________. A. observation, experimentation, hypotheses, theory B.experimentation, observation, theory, hypotheses C. observation, hypotheses, theory, experimentation D. hypothesis, theory,experimentation, observationAnswer: A2.Which of the following is NOT one of the key steps involvedin the scientific method? A. Formulating hypotheses B. Building experiments C. Rejecting hypotheses D. Proving hypothesesAnswer: D3.Which of the following is a physical property? A. Density B.Flammability C. Reaction with acid D. RustingAnswer: A4.Which subatomic particle carries a positive charge? A.Proton B. Neutron C. Electron D. AtomAnswer: A5.Which of the following is NOT a chemical change? A. Burningof wood B. Digestion of food C. Melting of ice D. Rusting of ironAnswer: CShort Answer Questions1.What is the difference between a chemical and physicalchange? Answer: A physical change is a change in the physicalproperties of a substance, whereas a chemical change is a change in the chemical properties or composition of a substance.2.What is an atom? Answer: An atom is the smallest particle ofmatter that retns the chemical properties of an element.3.What is a molecule? Answer: A molecule is a group of two ormore atoms that are chemically bonded together.4.What is an element? Answer: An element is a pure substancethat cannot be broken down into simpler substances by chemical means.5.What is a compound? Answer: A compound is a pure substancemade up of two or more elements that are chemically bondedtogether.Essay Questions1.What is the scientific method and how is it used to solveproblems in science? Answer: The scientific method is a logical and systematic approach to problem solving in science. It consists of several key steps including observation, hypotheses,experimentation, and theory. Scientists use the scientific method to answer questions and solve problems by gathering data through observation and experimentation, forming hypotheses based on that data, testing those hypotheses through experimentation, andfinally developing theories to expln the results of those experiments.2.Describe the properties of matter and how they are used to differentiate between substances. Answer: Properties of matter can be either physical or chemical. Physical properties include mass, volume, density, color, melting point, boiling point, and solubility. These properties can be used to differentiate between substances by comparing their physical properties. Chemical properties include reactivity, flammability, and toxicity. These properties are used to differentiate between substances based on their chemical behavior under certn conditions.3.Describe the structure of an atom and the role that subatomic particles play in determining chemical behavior. Answer: Atoms have a central nucleus that contns protons and neutrons. Electrons orbit around the nucleus in shells or orbitals. Protons carry a positive charge, electrons carry a negative charge, and neutrons carry no charge. The number of protons in the nucleus determines the element to which the atom belongs, while the number of electrons in the outermost shell determines the chemical behavior of the atom.4.Expln the difference between a mixture and a pure substance. Give examples of each. Answer: A mixture is a combination of two or more substances that are not chemically bonded together. Mixtures can be either homogeneous or heterogeneous. A homogeneous mixture is a uniform mixture where the composition is the same throughout, such as saltwater. A heterogeneous mixture is a non-uniform mixture where the composition varies, such as oil and water. A pure substance is a substance that cannot be broken down into simpler substances by chemical means. Examples of pure substances include elements such as gold and silver, and compounds such as water and carbon dioxide.5.Expln the difference between a physical change and a chemical change. Give examples of each. Answer: A physical change is a change in the physical properties of a substance, such as shape, size, or state of matter, without changing its chemical composition. Examples of physical changes include melting ice, boiling water, and cutting paper. A chemical change is a change in the chemical properties or composition of a substance, resulting in the formation of a new substance or substances. Examples of chemical changes include burning of wood, digestion of food, and rusting of iron.。
