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Chemistry Review Quest #2. Flame Test Density Lab Atomic Model History-Venn Diagram Chemical Formulas & counting atoms Classifying matter( pure substances-elements and compunds ; mixtures-Heterogeneous and Homogeneous) Lab Safety, Safety Symbols (WHMIS and MSDS) and Bunsen Burner
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Chemistry ReviewQuest #2 • Flame Test • Density Lab • Atomic Model History-Venn Diagram • Chemical Formulas & counting atoms • Classifying matter( pure substances-elements and compunds; mixtures-Heterogeneous and Homogeneous) • Lab Safety, Safety Symbols (WHMIS and MSDS) and Bunsen Burner • Physical properties & changes • Chemical properties & changes
Counting Atoms • The symbol of an element represents one atom of that element. • E.g. Na = One Sodium Atom • E.g. NaCl = One Sodium Atom + One Chlorine Atom
Counting Atoms - Subscripts • A subscript is a number written at the lower right corner beside the symbol of an element. • If there is more than one atom of the element, then a subscript is used to indicate the number of atoms. • E.g. H2 = Two Hydrogen Atom • E.g. H2 O = Two Hydrogen Atom + One Oxygen Atom
Check Your Understanding • The compound FeO2 contains how many atoms?
Check Your Understanding • The compound FeO2 contains how many atoms?
Check Your Understanding • The compound FeO2 contains how many atoms?
Check Your Understanding • The compound FeO2 contains how many atoms?
Yes Homogeneous mixture Yes
Mixtures PureSubstances Homogeneous Mixtures (Solutions) Heterogeneous Mixtures Elements Compounds Water, H20 Salt, NaCl Gold, Au Oxygen, O Oil and water Salt & Pepper Gatorade Salt and Water Classification of Matter: Pure compounds are represented with chemical formula! Mixtures can’t be represented with formulas!
WHMIS • We know with the help of symbols • WHMIS – used in workplace and schools • W – Workplace • H – Hazardous • M – Materials • I – Information • S - System
Guess What the Symbols Are! Flammable & combustible material Corrosive material Oxidizing material Biohazardous infectious material
Guess What the Symbols Are! Poisonous & infectious causing immediate and serious toxic effects Dangerously reactive material Compressed gas Poisonous & infectious causing other toxic effects
WHMIS Classifications All substances within a Class will have similar properties or hazards CLASS A: COMPRESSED GAS This class includes compressed gases, dissolved gases, and gases liquefied by compression or refrigeration. The symbol for Class A is a gas cylinder (think helium for balloons) inside a circle.
CLASS B: FLAMMABLE AND COMBUSTIBLE MATERIAL This class includes solids, liquids, and gases capable of catching fire in the presence of a spark or open flame under normal working conditions. The symbol for Class B is a flame inside a circle.
CLASS C: OXIDIZING MATERIAL These materials increase the risk of fire if they come in contact with flammable or combustible materials. This means that they allow certain substances to catch on fire more easily. The symbol is a circle that is on fire inside a larger circle.
CLASS D: POISONOUS AND INFECTIOUS MATERIAL - 3 DivisionsDivision 1: Materials Causing Immediate and Serious Toxic Effects - These materials can cause death or immediate injury when a person is exposed to small amounts. Examples: sodium cyanide and hydrogen sulphide. The symbol is a skull and crossbones inside a circle.
CLASS D: POISONOUS AND INFECTIOUS MATERIALDivision 2: Materials Causing Other Toxic EFFECTS - These materials can cause life-threatening and serious long-term health problems as well as less severe but immediate reactions in a person who is repeatedly exposed to small amounts. The symbol is an exclamation point that looks like a T inside a circle.
CLASS D: POISONOUS AND INFECTIOUS MATERIALDivision 3: Biohazardous Infectious MATERIAL - These materials contain harmful micro-organisms that have been classified into Risk Groups 2, 3, and 4 as determined by the World Health Organization (WHO) or the Medical Research Council of Canada. This symbol is often found on medical waste. It looks like 3 C’s combined together with a circle on the inside. It is inside a larger circle.
CLASS E: CORROSIVE MATERIAL This class includes caustic and acid materials that can destroy the skin or eat through metals. Examples: sodium hydroxide, hydrochloric acid, nitric acid. The symbol is two test tubes being poured onto a metal bar and a hand and it is inside a circle.
CLASS F: DANGEROUSLY REACTIVE MATERIAL These products may self-react dangerously (for example, they may explode) upon standing or when exposed to physical shock or to increased pressure or temperature. They may emit toxic gases when exposed to water. The symbol is an R with a test tube inside it and is inside a circle.
Safety Tips • キNever use your fingers to hold an object in the Bunsen burner flame. Instead, use a pair of tongs to hold a small, solid object. • キAlways have long hair tied back, safety goggles on, no loose clothing, and keep all flammable chemicals away from the burner.
Steps for Lighting a Bunsen Burner: • 1. Close the needle valve most of the way, leaving the valve only slightly open. • 2. Connect the tubing to the burner's gas inlet nozzle and to the gas outlet nozzle at the bench. • 3. Turn on the source of the methane gas. • 4. Slowly turn the needle valve a small amount to supply gas to the burner. • 5. To ignite the gas using a striker, hold the striker at the side of the outlet of the burner tube and squeeze and release until a spark ignites the flame.
Physical Properties • Physical Properties: can be observed or measured without changing the identity of the substance. They are characteristics of a substance. Examples: Colour, odor, taste, luster, hardness, tecture, conductivity, state of mater, malleability, ductility, solubility, density, etc.
Physical Changes • Physical Changes: changes that affect one or more physical properties, but do not change the identity of the substance. Changes include: size, state of matter, shape and sometimes color. No new substance forms.
Examples of Physical Changes: *Physical changes can be undone
Chemical Properties • Chemical Properties: describe how one substance changes into another substance with different properties. They show how things interact with each other.
Chemical Changes • Chemical Changes: a process by which a substance changes. Occurs when a substance is changed into an entirely new substance with different physical properties. Any chemical change is also a physical change.