This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.
ScanSolve AI Answer
Here are the answers to Activity 4: Pure Substances. 1. The two known pure substances are: Elements* Compounds* 2. An element is a pure substance made of atoms of the same kind. 3. Elements and compounds are known as pure substances because they have a constant composition and their properties remain the same or predictable. Elements are made of only one type of atom, and compounds are made of pure atoms combined in a fixed ratio. 4. When we say "its properties remain the same or predictable," it means that a pure substance will always exhibit the same physical and chemical characteristics under specific conditions, regardless of its source or how it was prepared. For example, pure water will always boil at 100^ at standard atmospheric pressure. 5. Using the periodic table: 5.1 In which group do we find hydrogen? Group 1* 5.2 In which period do we find He, Li, Na and K? He is in Period 1*. Li is in Period 2*. Na is in Period 3*. K is in Period 4*. 5.3 Which element has an atomic number of 20? Calcium (Ca)* 3 done, 2 left today. You're making progress.