Chemistry Notes. Atom – the building blocks of matter Element – Elements are made up of atoms. Any substance that contains only one kind of an atom. Examples: hydrogen, carbon, oxygen, sodium, chlorine Compound – two or more elements that have combined
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Atom – the building blocks of matter
Element– Elements are made up of atoms. Any substance that contains only one kind of an atom.
Examples: hydrogen, carbon, oxygen, sodium, chlorine
Compound– two or more elements that have combined
Examples: table salt, water, carbon dioxide
Chemical formula – shorthand way of describing a chemical compound.Examples: NaCl H2O CO2
Electron-Dot diagram – way to represent molecules and compounds
Valence electrons are in the outermost energy level and are represented as dots around an element’s symbol
Examples: H C O Na Cl
When you have two different elements, there are usually only two words in the compound name. The first word is the name of the first element. The second word tells you the second element and how many atoms there are in the compound. The second word also ends in IDE. That's the suffix. When you are working with non-metals like oxygen (O) and chlorine (Cl), the prefix of the second element changes based on how many atoms there are in the compound.
Carbon Monoxide = 1 carbon, 1 oxygen
Carbon Dioxide = 1 carbon, 2 oxygen
Carbon Tetrachloride = 1 carbon, 4 chlorine
3 types of chemical bonds
Chemical Reactions = a chemical change in which molecules rearrange to produce a new substance.
Evidence of a chemical reaction
Bubbles, Heat released, Heat absorbed, Light, or Color change
In EVERY chemical reaction, energy is absorbed or released.
Endothermic reaction is when energy is absorbed. Ex: cold pack, refrigerator, or photosynthesis, ice cream in a baggie
Exothermic reaction is when energy is released. Ex: hot pack, digestion, fireworks
Catalyst = speeds up a chemical reactionExamples: Enzymes in your body, catalytic converter in cars, or salt causing rust on a car to speed up
Inhibitor = slows down a chemical reactionExamples: food preservatives, antibiotics or some paints or oils slow down rusting.
Chemical Equation = is a sentence that describes what happens in a reaction. (needs to be balanced on both sides)
Reactant: substance you start with
Product: substance you end with
+ means and
1) Respirationoxygen + glucose sugar carbon dioxide + water + heat energy6O2 + C6H12O6 6CO2 + 6H2O + heat energy
2) Photosynthesis chlorophyll carbon dioxide + water +light energy glucose sugar + oxygen6CO2 + 6H2O + light energy 6O2 + C6H12O6
5) wood + oxygen + (energy) carbon dioxide + water + (energy)
The rate of a reaction is the speed at which a reaction happens. If a reaction has a low rate, that means the molecules combine at a slower speed than a reaction with a high rate.
Concentration, pressure and temperature can effect the rate of the reaction.