Unit 1: Matter and Qualitative Analysis PDF

**Unit 1: Matter and Qualitative Analysis** **Activity 1: Introduction to Chemistry** **Classifying Matter** Matter is anything that has mass and occupies space. It can be it can be divided into groups: pure substances and mixtures. +-----------------------------------+--------------------------...

**Unit 1: Matter and Qualitative Analysis** **Activity 1: Introduction to Chemistry** **Classifying Matter** Matter is anything that has mass and occupies space. It can be it can be divided into groups: pure substances and mixtures. +-----------------------------------+-----------------------------------+ | A pure substance has a constant | | | composition: all parts of the | | | substance are the same and its | | | properties remain constant. | | | Aluminium and sodium chloride are | | | examples of pure substances. | | | Although everything is made of | | | chemicals, pure substances are | | | often referred to as chemicals | | | since their chemical composition | | | is completely described in their | | | name, i.e. potassium chloride is | | | just potassium bonded to chlorine | | | whereas sand is a large and | | | anonymous collection of | | | chemicals. | | | | | | Pure substances can be further | | | divided into compounds and | | | elements. Elements are made up of | | | only one type of atom, such as | | | oxygen or aluminium. | | +-----------------------------------+-----------------------------------+ Compounds are made up of two or more elements combined in a fixed ratio to make a new substance, such as H~2~O, or NaCl, which we know by their respective common names as water and salt. Mixtures can be divided into two groups: heterogeneous and homogeneous. In homogeneous mixtures, all parts look the same. For example 1, many beverages are made up of water, sugar, and numerous colour and flavouring chemicals, but you can\'t see these parts individually in the mixture. In chemistry, homogeneous mixtures are often referred to as solutions. On the other hand, heterogeneous mixtures are made up of parts that can be visually distinguished in the mixture. For example, salsa is made up of tomatoes, peppers, onions, and spices. It is possible to see each one of these ingredients in the mixture. Soda drinks or "pop" are made of a liquid and dissolved carbon dioxide which becomes a heterogeneous mixture once the container is opened. When all the "fizz" is gone the drink is no longer liquid and gas but only liquid---it now tastes "flat" since the tiny bubbles are absent. Mixtures display varying properties depending on the proportions of the different components in the mixture. **Atoms and Ions** The atom is the smallest particle of an element that can exist on its own and retains its distinguishing chemical properties. It is made up of three main components. The protons and neutrons form the dense nucleus in the center of the atom, while the electrons travel around the nucleus of the atom in paths called orbits. The diagram above shows the general shape and parts of the atom, but the size of the nucleus is much smaller in relation to the electrons. If the electrons were portrayed next to a nucleus of the correct size as shown they would be over 20 km away! If an atom loses or gains an electron it becomes an ion. When an atom loses electrons, which have a negative charge, the atom becomes a positive ion called a cation. If an atom gains electrons it becomes a negatively charged anion. **Atomic Number** The atomic number of an atom corresponds to the number of protons the atom contains. In a neutral atom, the number of protons is also equal to its number of electrons. The atomic number is represented by the letter Z. **Mass Number** The mass number represents the sum of the number of neutrons and protons in an atom. It is represented by the letter A.  Given just how small an atom is, we can\'t measure using typical \"weight\" units (like grams or pounds), so we use something called \"atomic mass unit\" (or a.m.u.) A = Z + N -------------------------------------------------------------------- where Z is the number of protons, and N is the number of neutrons. The equation can also be rearranged to calculate the number of neutrons in an atom. Number of Neutrons (N) = mass number -- atomic number ------------------------ --- ------------------------------ N = A -- Z ** Example 1** Iron has an atomic number 26. Its mass number is 56. Calculating the number of neutrons we would get: Number of Neutrons = mass number -- atomic number -------------------- --- ------------------------------ = 56a.m.u. -- 26protons = 30neutrons The iron atoms have 30 neutrons. **Isotopes** Isotopes are atoms of an element that have the same number of protons but different numbers of neutrons, and therefore have a different mass number. Isotopes are named by using the element\'s name followed by it mass number. **Example 2** The element carbon has 3 isotopes: carbon-12, carbon-13 and carbon-14. All carbon atoms have 6 protons, therefore carbon-12 has 6 neutrons, carbon-13 has 7 neutrons and carbon-14 has 8 neutrons. **Radioisotopes** A radioisotope is an atom with an unstable nucleus, which is a nucleus with excess energy. The radioisotope undergoes radioactive decay, and emits a form of energy, called gamma rays, along with subatomic particles, such as neutrons and protons. Radioisotopes may occur naturally, or can also be artificially produced.\ \ In the interactive activity below, C-14 is considered a radioisotope.   **Safety with Chemical** All workplaces in Canada, including schools, use a standardized system of symbols to identify potentially hazardous materials. This safety system is called WHMIS: Workplace Hazardous Materials Information System. The WHMIS 2015 symbols are found on the product labels of the containers in which materials are stored. Some examples of WHMIS 2015 symbols include: ------------------------------------- --------------------- --------------------------------------------------- ------------------------------------ \ Corrosion Corrosion \ Flame\ Health Hazard Materials Causing Acute (Immediate) Toxic Effects Flammable and Combustible Material ------------------------------------- --------------------- --------------------------------------------------- ------------------------------------ +-----------------------------------+-----------------------------------+ | The WHMIS symbols are | | | complemented with ratings for | | | health, flammability, physical | | | hazard, and required personal | | | protection on the product labels. | | | The system utilizes coloured | | | bars, numbers and symbols to | | | convey the hazards of workplace | | | chemicals. | | | | | | Each one of the three sections is | | | given a rating from 0 to 4, where | | | 0 represents no danger and 4 | | | represents the highest degree of | | | danger. The bottom section uses | | | letters, to indicate the personal | | | protective equipment needed when | | | using that chemical, the higher | | | the letter the more protection is | | | needed. | | +-----------------------------------+-----------------------------------+ ** Example** -- -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Here, ethanol is assigned a health hazard of 1, a flammability of 3, and a physical hazard of 0. The level of personal protective equipment (PPE) is C. This means safety glasses, gloves and an apron should be worn when working with this chemical. -- -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- **Material Safety Data Sheets (MSDS)** To give workers more information, WHMIS labelled products also come with a Material Safety Data Sheet to provide more information about the product. Material Safety Data Sheets are prepared by the chemical supplier, must be updated every three years, and be available to workers at all times in a convenient location. The Material Safety Data Sheet for a product contains information on: - product Information - hazardous Ingredients - physical properties - fire and explosion risks - reactivity data and health hazards - preventative measures - first aid measures