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Chap. 2 : Chemistry
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Makeup of matter --- matter – anything that has mass and takes up space. (volume)
A. Atoms – simplest particle of an element. 1. Nucleus – center of atom, contains protons (p+) and neutrons (n). p n = atomic mass 2. electrons – (-) charge, orbit around nucleus in shells or orbitals. 3. neutrons (n) – atomic mass – atomic number
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*** atomic number – tells # of p+, e-.
B. Orbitals - family – row going down, tells # of e- in outer shell. - period – row going across, tells the # of electron shells. *** All atoms want to be stable !! Stable arrangements are having a full outer shell which is 8e- or 2e-(if only 1 shell)
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*** e- in shells : 1st – 2e- 2nd – 8e- 3rd – 18e- 4th – 7th – 32e-
C. Bonding – atoms bond to become stable Ionic bonds – transfer of e-, forms ions. Done between families 1,2,3,5,6,7 . Ex. Na + Cl NaCl
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--- elements combine to form compounds. Ex. H2O , C6H12O6
2. Covalent – sharing of e-. Done with family 4 and also H. Ex. H + Cl HCl D. Elements – purest substance – cannot be broken down into anything simplier. --- elements combine to form compounds. Ex. H2O , C6H12O6 --- molecule – smallest part of a compound.
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III. Chemical Reactions A. Na + Cl NaCl
II. Energy – ability to do work activation energy – amount of energy needed to start a chemical reaction. (enzymes lower activation energy) III. Chemical Reactions A. Na Cl NaCl (reactants) (yields) (products) -- subscript – tells # of atoms of 1 particular element. Ex. H2(subscript) -- coefficient – tells # of
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** subscript x coefficient = total # of atoms of a particular element.
molecules of a particular element or compound. Ex 2H2O (2 molecules of water) ** subscript x coefficient = total # of atoms of a particular element. ex. 6C4H8O4 ___ C ___ H ___ O B. Energy Transfer in Reactions 1. Exergonic Reactions – release energy (feel hot)
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2. Endergonic reactions – absorb energy (feel cold).
IV. Solutions - mixture of one or more substances. Made up of : a. – substance being dissolved solute. b. solvent – substance being dissolved into. ex. Sugar (solute) water(solvent)
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2. Hydronium ion (H+) – solution with more H+ than OH-.
IV. Acids/Bases Hydroxide ion (OH-) – solution with more OH- than H+. Becomes basic (alkaline). 2. Hydronium ion (H+) – solution with more H+ than OH-. Becomes acidic. pH scale blood ammonia Acidic HCl neutral (H20) basic
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each increase in pH scale # is 10x greater than the # before
** each increase in pH scale # is 10x greater than the # before. 4 is 100x more acidic than 6. Buffers – neutralize acids or bases. Ex. Tums, rolaids
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