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What is the best method to classify a chemical substance? - Coggle Diagram

- - - - Pure substances
        
        Elements
        
        An element is a fundamental substance that cannot be broken down into simpler substances by ordinary chemical means. It consists of atoms, all of which have the same number of protons in their atomic nuclei (TeachTarget, n.d)
        
        Compounds
        
        A compound is a substance composed of two or more elements that are chemically bonded together in fixed proportions (TeachTarget, n.d)
        
        The type of bonding in a compound depends on the types of atoms involved and their arrangment.
      - Mixtures
        
        Heterogeneous mixtures
        
        A heterogeneous mixture is a type of mixture where the components are not uniformly distributed throughout the mixture. In other words, it is a mixture that consists of visibly distinct substances or regions with different properties (Chemistry LibreTexts, n.d)
        
        Homogeneous (solution) mixtures
        
        A homogeneous mixture, also known as a solution, is a type of mixture where the components are uniformly distributed throughout the mixture at a molecular level. In other words, it is a mixture that appears the same throughout and has a uniform composition (BYJU'S, n,d)
  - - - Covalent bonding is a type of chemical bonding that occurs between atoms when they share electrons in order to achieve a stable electron configuration (BYJU'S, n.d)
        
        Physical properties
        
        They have a low boiling and melting point. They are poor conductors of electricity. They are soluble in polar solvents such as water.
        
        Examples of substances with covalent bonding include Hydrogen (H) and Oxygen (O)
      - Covalent molecular
        
        A molecular substance, also known as a covalent molecular compound, is a type of chemical compound composed of molecules. It consists of two or more atoms that are chemically bonded together by a covalent bond, forming a stable structure. These atoms can be of the same element or different elements (Study.com, 2021)
      - Covalent netwrok
        
        Covalent Network Solids are giant covalent substances like diamond, graphite and silicon dioxide (silicon(IV) oxide). (Chemistry LibreTexts, 2023)
    - - An Ionic bond is the bond formed by the complete transfer of valence electron to attain stability (BYJU'S, n.d)
        
        Physical properties
        
        They are soluble in water. They have a high boiling and melting point. They are poor conductors of electricity when solid, but are conductors when melted or dissolved.
        
        Example of substances with ionic bonding include Sodium (Na) and Chlroine (Cl)
    - - Metallic bonding is a type of chemical bonding that occurs in metals. It is characterised by the sharing of valence electrons among a lattice of metal atoms, leading to the formation of a unique structure and distinctive properties (Britannica, n.d)
        
        Physical properties
        
        They are malleable. They are ductile. They mostly have a high boiling and melting point. They are good conductors of heat and electricity.
        
        Example of substances with metallic bonding include copper (Cu) and Iron (Fe)
      - Metals
        
        Metals generally have a lustrous or shiny appearance when freshly cut or polished. They also have high electrical and thermal conductivity (BYJU'S, n.d)
        
        Metals tend to be more reactive, especially with acids and oxygen. They can easily lose electrons and form positive ions.
        
        Metals generally have high melting and boiling points. They tend to have strong metallic bonds, which require a significant amount of energy to break.
      - Non-metals
        
        Non-metals can have a variety of appearances. Some non-metals like sulfur are brittle solids, while others like oxygen and nitrogen are gases at room temperature (BYJU'S, n.d)
        
        Non-metals can be reactive or non-reactive depending on the element. Some non-metals like fluorine and chlorine are highly reactive, while others like noble gases are very stable and unreactive.
        
        Non-metals have lower melting and boiling points compared to metals.
  - - - Substances can differ in their physical properties, such as melting point, boiling point, density, colour, odor, and solubility. These differences arise from variations in intermolecular forces, molecular size and shape, and other factors that influence how the substance interacts with its surroundings (OpenStax, n.d)
    - - Substances can exhibit different chemical properties. They may have different reactivity patterns, such as their ability to undergo specific types of chemical reactions, their acidity or basicity, or their stability under certain conditions (OpenStax, n.d)
    - - The arrangement and connectivity of atoms within a molecule can differ between substances. Even substances with the same chemical composition can have different structures, resulting in distinct properties (Britannica, n.d)
- - - - These tests investigate how a substance reacts with other substances or under specific conditions.
        
        For example, a substance can be tested for its reactivity with water, heat, and acids. Reactions such as precipitation, gas evolution, colour changes, or temperature changes can help determine the substance's classification (Office of Scientific and Technical information, 2016)
        
        Limitation for these type of tests
        
        Chemical reactivity tests rely on their sensitivity to detect even the smallest changes or reactions. However, some reactions may be slow, require specific catalysts or conditions, or produce low levels of observable changes. If the test lacks sensitivity, it may not be able to detect or quantify certain reactions accurately.
    - - These tests examine the physical characteristics of a substance. They include tests such as measuring the substance's melting point, boiling point, density, solubility, conductivity, or appearance. These properties can provide valuable information for classifying substances (Americhem, n.d)
        
        What is solubility and how to determine it?
        
        Solubility refers to the ability of a substance, known as the solute, to dissolve in a solvent to form a solution (homogeneous mixture). It is a measure of how much solute can dissolve in a given amount of solvent at a specific temperature and pressure (Britannica, 2023)
        
        What is boiling/melting point?
        
        The melting point of a substance is the temperature at which it changes from a solid to a liquid phase (Britannica, 2023)
        
        The boiling point of a substance is the temperature at which it changes from a liquid to a gas at a specific pressure (Melting point, n.d)
        
        Limitation for these type of tests
        
        Physical properties can be influenced by external factors such as temperature, pressure, and humidity, making it difficult to compare results obtained under different conditions.
- - - - Differenec in the size of the sample (substance given) may results in variations in the observed properties and impact the classification outcome.
    - - Changes in temperature and humidity can change the properties of the substance, such as its melting point or solubility. These variations can impact the classification process and make it challenging to obtain consistent results.
  - - - Inaccurate use of measurement instruments, such as balances, thermometers, or spectrometers, can introduce errors in the experimental data. These errors can impact the classification results.
    - - Classifying a substance requires accurate and comprehensive information about its properties, composition, and behavior. If the available data is inaccurate, incomplete, or outdated, it can lead to misclassification. It is crucial to ensure that the data used for classification is reliable and up-to-date.