Tài liệu hướng dẫn học tiếng anh | Academic English Program PHAN THANH TRUNG LESSON 1 1. READING Chemical Equations Scientists believe that elements consist of atoms. Atoms are the smallest pieces of elements. Elements combine to form compounds. When this happens the atoms of each element stick or bond together. These bonded atoms from molecules. When two atoms of Hydrogen H combine with one atom of Oxygen O2 they form one molecule of water H2O . Chemical equations show what happens when the compounds combine. For example H2O SO2 H2SO3. In this equation sulfur dioxide SO2 combines with water H2O to yield sulfurous acid H2SO3 . We often combine compounds of unequal amounts. Then we write a number before the symbol for the compound. For example 5O 2 means 5 parts of oxygen. 1. According to the passage atoms A are larger than molecules B are the largest pieces of elements C are smaller than molecules D combine to form compounds 3. The word yield in the paragraph 2 is closet in meaning to A produce B stick together C unequal D allow 2. Which is true of compounds A They are smaller than molecules B They are smaller than atoms C They are the same as elements D They are formed when elements combine. 1 To remove this message purchase the product at This document was created using NVERTER PDF Academic English Program PHAN THANH TRUNG 4. Explain or show the relationship between atoms molecules and compounds. WILDERNESS FIRST AID In the woods people are alone and far from help. Thinking ahead can help avoid getting hurt. On long trips it is a good idea to bring a fir st aid book and a medical bag. A list of important items should be prepared and checked before leaving. A fi rst aid bag with treatment for cuts should always be prepared and taken. It should also have medicine for bug bites pain and other maladies. Also it is important to know what to do. A medical bag full of items is useless if no one knows how to use them. The use of these items should be clearly understood. They may be needed
