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42 Cards in this Set
- Front
- Back
The Six Changes Of State
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~ Liquid to Solid – Freezing or Solidification
~ Solid to Liquid – Melting ~ Solid to Gas – Sublimation ~ Gas to solid – Deposition ~ Liquid to Gas – Evaporation ~ Gas to Liquid – Condensation |
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Two Properties of Matter
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~Physical: Describes the physical characteristics of a substance such as color, luster, density, hardness and crystal shape.
~Chemical: Describes how the substance reacts with other substances, An example would be vinegar and baking soda reacting |
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Pure Substances: Elements
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A substance that cannot be broken down further
Ex) Gold |
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Pure Substances: Compounds
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~A chemical combination of two or more elements in a fixed proportion
~Ex) NaCI (Sodium Chloride) ~Compounds have a very strong chemical bond. As the elements combine they lose their individual characteristics ~Compounds cannot be separated by physical means such as evaporation |
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Mixtures: Mechanical Mixtures
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~You see more than one mixture
~Ex) Cookie Dough ~These are also called Heterogeneous mixtures ~These can be separated by mechanical means such as using hands or filters |
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Mixtures: Solutions
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~A mixture where you cannot see the different parts
~Example: Vinegar ~These are also called homogeneous mixtures ~There is no settling in a solution ~There are no chemical bonds in solutions. When the substances join, they keep their individual characteristics. ~Solutions happen because the particles slip between each other so they are evenly distributed ~They can be separated by physical means such as boiling |
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Mixtures: Suspensions
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~Suspensions are heterogeneous mixtures that look homogeneous.
~Over time, the particles settle out in a suspension. ~The particles can be separated by filters or leaving it stand over time. ~Example: Salty water |
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Mixtures: Colloids
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~These are heterogeneous mixtures in which the particles don’t settle out.
~Colloid particles can often be seen in a beam of light. ~Example: Milk is a colloid |
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Physical Change
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~A physical change is a change in appearance or state of a substance. Composition of the substance always stays the same.
~Example: Melting, crystallization |
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Chemical Change
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~This occurs when two or more substances react and create new substances.
~Example: Vinegar and baking soda reacting |
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Evidence of Chemical Change
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1. Change in color
2. Change in odour 3. Forming a solid or gas 4. Release or absorption of heat energy |
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Democratis
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Greek philosopher that believed that matter could be broken down into indivisible bits called “atomos”
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Aristotle
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Another Greek philosopher that believed that everything was made of earth, air, fire and water.
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Robert Boyle
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~Experimented with gases and what happened to them under pressure
~Through experiments he became convinced that matter was made of tiny particles |
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Antoine Lavoisier
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~Known as the “father of modern chemistry,” he developed a system for naming chemicals
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John Dalton
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~First person to define an element as a pure substance
~Came up with the “billiard ball” model of the atom, which was the first theory of atomic structure |
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J.J Thomson
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~Discovered electrons and came up with the “raisin bun” or “plum pudding” model of the atom: This showed the atom as a positive sphere with electrons (negative charges) embedded in it
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Hantaro Nagaoka
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~Proposed the “solar system” model of the atom: This showed the atom as a positive sphere with electrons orbiting it
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Niels Bohr
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~Develops the “electron shell” model where electrons move in specific shells or orbits around the nucleus
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James Chadwick
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~Discovered the proton (positive charge) and the neutron (no charge) in the nucleus
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Electrons
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Negatively charged subatomic particles found in the cloud region of atoms
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Protons
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Positively charged subatomic particles found in the nucleus
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Neutrons
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Neutral subatomic particles found in the nucleus
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Atoms
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The basic building blocks of all matter.
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Molecules
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A group of at least two atoms held together by chemical bonds.
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Types of Elements: Metals
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~Are on the left side of the staircase…they are shiny, malleable, and ductile and conduct electricity.
~Alkali metals are the most reactive metals. |
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Types of Elements: Non Metals
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~Are on the right side of the staircase…they are dull, brittle and nonconductive. They can be a solid or gas.
~Halogens (group 17) are the most reactive non-metals. |
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Types of Elements: Noble Gases
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~Are in group 18 and are the most stable and un-reactive elements.
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Types of Elements: Metalloids
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~Are directly above and below the staircase…they show properties of both metals and non-metals.
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Ions
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~An ion is an atom or group of atoms that has become electrically charged
~Ionic compounds are pure substances that form as a result of the attraction of positive and negative ions |
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Ionic Compounds
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~They:
Are solids at room temperature Have defined crystal structure Conduct electricity when liquid or dissolved in water Have high melting points |
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Molecular Compounds
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~Can be solids, liquids or gases at room temperature
~Do NOT conduct electricity when liquid or dissolved in water ~Have low melting points |
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Exothermic Chemical Reaction
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~A chemical reaction that releases energy is called exothermic
~ Energy released can be heat, light, sound, and electricity ~Example: Burning wood |
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Endothermic Chemical Reaction
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~A chemical reaction that absorbs or requires energy is called endothermic
~ Many require heat but could also require electricity or UV radiation ~Example: Cooking food or recharging a battery |
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Reactions with Oxygens
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~Combustion
>Occurs when oxygen reacts with a substance to produce a new substance and energy ~Corrosion >Occurs when oxygen in the atmosphere gradually reacts with a metal producing rust ~Cellular Respiration >Occurs in only in cells and is the reaction of organic material (food) with oxygen |
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The Law of the Conservation of Mass
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~States that the total mass of the reactants is equal to the total mass of the products in every chemical reaction
~When a chemical reaction takes place, matter is not created or destroyed, it is only rearranged |
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Closed System
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~Is a system where matter cannot escape
~Example: a reaction in a sealed flask |
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Open System
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~Is a system where matter can escape
~Example: a reaction in an open beaker |
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Reaction Rate
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1. Presence of a Catalyst:
~Substances that help a reaction proceed faster without being used up themselves ~Can be found in non-living and living systems ~Example: enzymes in your body 2. Concentration of the Reactants ~A higher concentration of reactants means there are more particles around to bump into each other and react 3. Temperature of the System ~ Higher temperature speeds up the motion of the particles that makes them bump into each other and react 4. Surface area of the Reactants ~A higher surface area of the reactants means more particles are exposed and able to react with other reactant particles |
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Enzyme Vs. Inorganic Catalyst
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An enzyme is an organic catalyst made of protein, and functions in living things to influence
the rate of biological reactions. An inorganic catalyst can influence the rate of a reaction in a non-living system. |
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Organizing Elements
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John Newlands recognized patterns in properties when elements were listed in order of atomic mass. He said properties of elements seemed to repeat every 8 intervals on the list
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Dimitri Mendeleev
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came up with a pattern for the elements based on their properties
~He listed the 63 known elements at the time according to their properties and left gaps for elements he was sure would be discovered in the future |