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Published byDerick Bryant Modified over 8 years ago
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Composition of Matter Section 1
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Matter and Mass Matter - anything that occupies space and has mass Mass – quantity of matter an object has – Mass is not the same as weight
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Matter 1. Substance – can write chemical formulas 2. Mixtures – made of different substances in variable ratios – Homogeneous – solutions – Heterogeneous – mixture of physically distinct substances with different properties
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Elements Elements – substances that cannot be broken down chemically into simpler kinds of matter Most common elements in living things: – O – C – H – N
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Atoms Atom – simplest part of an element that retains all the properties of that element Mainly empty space Contain nucleus and outer energy levels Net charge = 0
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Parts of an atom Nucleus – Protons (+) – Neutrons (neutral) # protons=# electrons (except if its an ion) Orbital's – Electrons (-)
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Electrons and Orbital’s High energy & little mass Orbital’s – 3D region around a nucleus that indicates probable location of electron – Orbital’s further away have greater energy 1 st – 2 e- 2 nd – 8 e- 3 rd – 18 e- 4 th – 32 e-
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Specifics Atomic number= number of protons Mass number = protons + neutrons Chemical symbol = name of element
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Isotopes Isotope- atoms of same element that have different number of neutrons Since the number of neutrons is changing, what else will change?
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Compounds Compound – 2 or more elements that are chemically bonded Chemical formulas show # of atoms each element contributes to compound – Ex : Na 2 NO 3 Na= ? N= ? O= ? Chemically stable when outermost energy level is filled
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Atomic Structure Element/ Ion Atomic #Atomic Mass Mass Number ProtonsNeutronsElectrons H11.007941101 H+H+ 1 1100 12 6 C 7 3 Li + 35 17 Cl - 39 19 K 24 12 Mg 2+ As 3- Ag Ag +1 S -2 U
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Bonding Noble Gases – Far right column – Usually do not react w/ any other elements Chemical Bonds – Attractive forces that hold atoms together
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Covalent Bonds Covalent Bond – forms when 2 atoms share 1 or more pairs of electrons
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Ionic Bonds Ionic Bond – form when electrons are transferred from 1 atom to another
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Energy Section 2
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Activity List as many different types of energy as you can
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Energy Energy – ability to do work
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States of Matter
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Chemical Reaction Chemical Reaction – change in which a substance is changed into 1 or more new substances – Reactants – substance or molecule that participates in a chemical reaction – Products – substance that forms in a chemical reaction
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Rust Example 4Fe + 3O 2 = 2Fe 2 O 3 – Reactants? – Products?
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Chemical Reactions in the Body How does your body acquire energy? – Proteins, sugars and fats in food provide energy – Energy released in body after breaking these down Metabolism – all chemical reactions that occur in an organism
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Activation Energy Activation energy – amount of energy needed to start a reaction Catalyst – chemical substance that reduces amount of activation energy needed for reaction to take place
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Activation Energy Vs. Catalyst
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Enzymes Catalysts in the body Usually proteins or RNA
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Oxidation Reduction Reactions What part of an atom helps transfer energy in a chemical reaction? Redox Reaction – r(x) where e- are transferred between atoms Oxidation Reaction – reactant loses e- and becomes (+) charged Reduction Reaction – reactant gains e- and becomes (-) charged
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SECTION 2 REVIEW p.37 3. Describe the effect of an enzyme on the activation energy in a chemical reaction. 4. Enzymes are biological catalysts. Explain what they do in living systems.
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Water and Solutions Section 3
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Activity Out of a human body, elephant, ear of corn, and a tomato, construct a list of which contains the highest percent of water to the least amount of water.
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Answers – Tomato – 95% – Elephant – 70% – Corn – 70% – Human Body – 65%
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Polarity Polar – partial charge that is produced because the total charge is unevenly distributed – Makes water great solvent because other polar things are attracted to it
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Hydrogen Bonding Hydrogen Bond – force of attraction between a hydrogen molecule with a partial positive charge and another atom or molecule with a partial or full negative charge
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Cohesion Cohesion – attractive force that holds molecules of a single substance together – Creates surface tension
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Adhesion Adhesion – force between 2 particles of different substances – Creates capillary action
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Temperature in Moderation Specific Heat - amount of heat a substance can absorb without raising its own temperature Day – water absorbs energy from sun and cools air w/o large increase in water temp. Night – cooling begins and warms the air
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Solutions Solution – mixture in which 1 or more substances are uniformly distributed – Solute – substance being dissolved – Solvent – substance in which solute is dissolved – Various concentrations and becomes saturate when no more solute can dissolve Solute - salt Solvent - water
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Acids and Bases Give examples of an acid and a base. OH - = hydroxide ion H 3 0 + = hydronium ion H 3 O + > OH - = acid H 3 O + < OH - = base (alkaline)
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pH Scale Ranges from 0 – 14 – 0 – 6.9 = acid – 7 = neutral – 7.1 – 14 = base pH tested by litmus paper
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Buffer Buffer – chemical that neutralizes acid or base – Overall pH of body = 7 pH stomach acid =2 pH intestinal fluid = 8 pH blood = 7.5 Buffers neutralize these and maintain body pH at 7
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