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29 Cards in this Set
- Front
- Back
Reactants |
the original substances present in a chemical reaction |
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Products |
are what is produced by the reaction (reactants ------> products) |
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The Law of Conservation of Mass |
"Matter can neither be created nor destroyed during a chemical reaction" meaning that the matter/mass is not lost, it is just in a different form. |
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The Law of Constant Proportions |
"a compound, no matter how it is formed, always contains the same relative amounts of each element" meaning that no matter how they are rearranged they always have the same amount on each side, e.g. carbon dioxide (CO2) always conatins the same amounts of carbon and oxygen |
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Endothermic Reactions |
Energy is absorbed, there is a decrease in temperature e.g. ice pack |
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Exothermic Reactions |
Energy is released, there is an increase in temperature e.g. explosion, fireworks |
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What happens to Atoms and Bonds when chemical reactions occur? |
chemical reactions take place when bonds between atoms are broken and new bonds are formed, creating a new arrangement of atoms and at least one new substance. |
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Acids |
a chemical that reacts with a base to produce salt and water, they taste sour and are corrosive and are red on the pH scale (0-6 on the pH scale). they also turn blue litmus paper red. e.g. lemon juice, hydrochloric acid, lemonade etc. acids in solution contain H+ ions |
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Bases |
a chemical substance that will react with an acid to product salt and water. edible bases taste bitter and are purple on the pH scale (8-14 on the pH scale). they also turn red litmus paper blue. e.g. laundry detergent, soap, oven cleaner etc. bases in solution contain OH- ions. |
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What are the different tastes between acids and bases? |
Acids taste sour whereas acids taste bitter |
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What is a neutralisation reaction? |
A neutralisation reaction occurs when you add the right amount of an acid and base together, which produces salt and water (acids+bases --------> salt+water) when a solution is neutral it will be a 7 on the pH scale and is green with an indicator added. |
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Acid Rain |
Acid rain is rainfall made very acidic by pollution and contains dissolved chemicals,such as sulfur dioxide, so much so that it can wear away at statues, infect waterways and kill off animal life and make the water dangerous. Rain is generally a little bit acidic because of its reacting with carbon dioxide in the atmosphere. |
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pH scale |
a scale from 1 (very strong acid) to 14 (very strong base) that measures how acidic or basic a substance is. |
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Combustion Reaction |
chemical reaction in that a substance reacts with oxygen and heat is released, e.g. an explosion |
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Chemical Reaction |
a chemical change where one or more new substances are produced (rearranging of atoms which form new bonds.) |
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Metals with acids |
produce hydrogen (metal+acid --------> hydrogen) |
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Alkali |
alkali is a soluble base (meaning it dissolves in water) |
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Corrosive |
describes a chemical that wears away the surface f substances, especially metal. |
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Indicator |
a substance that changes colour when it reacts with acids or bases. the colour shows how acidic or basic the solution is. |
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Universal Indicator |
a mixture of indicators that changes colour as the strength of an acid or a base changes, indicating the pH of a substance. |
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Litmus |
A common type of indicator (usually paper) |
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Matter |
is anything that has mass and takes up space |
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Atoms |
are the basic units of matter and the defining structure of elements |
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Chemical Equations |
a representation of a chemical reaction using symbols of the elements to indicate the amount of substances, usually in moles, of each reactant and product |
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Word Equation |
a representation of a chemical reaction using the reactants and products in an equation. e.g,. hydrogen + oxygen ------> h2o |
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chemical energy |
energy stored in chemical bonds that is released during chemical reactions |
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Explosions |
example of a combustion reaction |
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Molecules |
made up of atoms held together by chemical bonds, the smallest particle of a chemical element that can exist |
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Explosive reaction |
large amount of energy released in a small amount of time |